South African Journal of Chemical Engineering, 2024
Cationic particles are commonly used as wet-end additives in papermaking processes. This study ev... more Cationic particles are commonly used as wet-end additives in papermaking processes. This study evaluates the effects of cationic cassava starch (CCS) on the mechanical strength of paper made from bacterial cellulose (BC). Acetobacter xylinum was utilised in the production of bacterial cellulose (BC) paper, whereas 3-chloro-2hydroxypropyl trimethyl ammonium chloride (CHPTAC) was employed in the etherification process of cassava starch to synthesize CCS. Papers containing CCS displayed a more compact surface structure compared to traditional wood-based papers, reaching a brightness level of 97.3 and improving thermal and mechanical characteristics, such as higher tensile strength and is suitable for use as a separator in battery fabrication processes. The results emphasise the possibility of using CCS as a sustainable option in paper production, offering enhanced environmental and mechanical efficiency.
This study introduces a sustainable method of producing a graphene nano sheet (GNS) from coconut ... more This study introduces a sustainable method of producing a graphene nano sheet (GNS) from coconut shells and investigates its application in GNS, Ni/GNS, and Zn/GNS electrodes for advanced energy storage devices. The GNS was synthesized in a scalable manner using a pyrolysis and impregnation technique, with its successful synthesis verified by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and electrical conductivity measurement characterizations. The study highlights the enhanced performance of Zn/GNS electrodes, which outperform both pure GNS and Ni/GNS variants. This superior performance is attributed to the smaller particle size of Zn (mean = 2.356 μm) compared to Ni (mean = 3.09 μm) and Zn’s more favourable electron configuration for electron transfer. These findings demonstrate the potential of bio-derived GNS composites as efficient, high-performance electrodes, paving the way for more sustainable and cost-effective energy storage solutions.
This study employs a cost-efficient method to create a pliable BC/rGO-NiCo-LDH electrode film on ... more This study employs a cost-efficient method to create a pliable BC/rGO-NiCo-LDH electrode film on a bacterial cellulose base. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, Xray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) analyses verified the incorporation of reduced graphene oxide (rGO) and nickel-cobalt layered double hydroxide (NiCo-LDH) into the bacterial cellulose structure. The BC/rGO-NiCo-LDH composite material exhibited high-temperature stability and achieved a specific capacitance of 311 F g − 1 at a scan rate of 0.1 mV/s, surpassing that of earlier cellulose electrodes. The electrode film showed exceptional mechanical capabilities, displaying flexibility and load resistance without any structural damage. The film's flexibility and lightweight properties were improved due to the low density of 0.656 g cm − 3 , which is a result of the nanoporous structure and intrinsic low density of rGO and cellulose. A retention ratio of 0.40 for storage modulus at a glass transition temperature of around 90 • C demonstrated positive mechanical performance. This cost-effective and uncomplicated synthesis approach produced a BC/rGO-NiCo-LDH electrode with potential. The material possessed favourable mechanical and electrochemical characteristics, making it suitable for wearable electronics.
Graphene was synthesized through a two-step pyrolysis method using waste candlenut (Aleurites mol... more Graphene was synthesized through a two-step pyrolysis method using waste candlenut (Aleurites moluccanus) shells as the precursor. Cerium (Ce)/graphene composites were prepared via an impregnation technique. The resulting graphene and Ce/graphene were characterized using various analytical methods, including Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The bio-carbon produced predominantly exhibited a graphene structure with flat carbon morphology and an interlayer distance of 0.33 nm. This structural information is supported by XRD data, which shows a broad and weak peak at 2θ = 26◦ corresponding to the C (002) plane, indicative of graphene presence. FTIR, XPS, and Raman spectroscopy further confirmed the presence of graphene through the detection of Csp2 aromatic bonds and the characteristic D, G, and 2D peaks. Notably, the performance of cerium can be enhanced by the incorporation of graphene, attributed to the large surface area and chemical interactions between Ce and graphene. Consequently, candlenut-derived graphene shows potential as a supportive material for modifying the properties of cerium, due to the current value of Ce/Graphene increase with presence of graphene, thereby opening avenues for various advanced applications, such as sustainable and high-performance energy storage systems.
Case Studies in Chemical and Environmental Engineering, 2024
Biodegradable bioplastics provide a promising solution to mitigate environmental harm from petrol... more Biodegradable bioplastics provide a promising solution to mitigate environmental harm from petroleum-based plastics. This study focuses on optimizing bioplastic films made from oil palm trunk starch (OPTS), using glycerol (10, 20, and 30 % v/w) as a plasticizer and modified with citric-acid epoxidized palm oil (CEPO). The bioplastics were formed using the solution casting method and analyzed for morphology, functional groups, diffraction peaks, thermal and mechanical properties, degradation time, and compostability. The optimal conditions were achieved with 30 % glycerol (Sample ST-CEPO-GLY30). The addition of glycerol enhances the thermal and mechanical properties, improves the biodegradability, and compostability of the bioplastics.
This study investigated the potential of porous silica material extracted from volcanic ash of Mo... more This study investigated the potential of porous silica material extracted from volcanic ash of Mount Sinabung, Indonesia, as a corrosion inhibitor. The new material was subjected to comprehensive analysis using the X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Search Engine Marketing (SEM), and Atomic Absorption Spectrophotometry (AAS). Corrosion test was conducted by coating the metal surface with synthesized silica. XRD data showed the presence of amorphous silica, while SEM indicated a rough and irregular pore cavity. Based on AAS characterization, the concentration of silica in the Mount Sinabung volcanic ash was 79.23 % (v/v) with a yield of 29.73 %(w/w). Furthermore, coated and uncoated iron plates, with grit variations of 800, 1200, 1500, and 2000, were tested against HCl 15 % (v /v) and NaCl 3.5 % (w /v) as model corrosive solutions. The SEM results showed that coated plates had fewer holes and cracks formation while the XRD analysis of the same samples presented a slight decrease in the intensity of iron phase. Among silica-coated iron plates, the 1500 grit variation had the lowest corrosion rate and the highest corrosion inhibitor efficiency in both HCl 15 % (v /v) and NaCl 3.5 % (w /v) corrosive solutions, recording efficiencies of 26.3 and 91.8 %, respectively.
To optimize the Laser-Induced Graphene (LIG) Janus membrane, this study investigated the effects ... more To optimize the Laser-Induced Graphene (LIG) Janus membrane, this study investigated the effects of membrane pore structure, polydimethylsiloxane (PDMS) coating sequence and addition of silver (Ag) nanoparticles on membrane distillation (MD) performance. This study aimed to enhance the photothermal characteristics of graphene while using the intrinsic electrical conductivity for simultaneous photo-and electrothermal MD. Operating at the same photo-and electro-thermal power input, the LIG Janus membrane made by treating the membrane face with smaller pores (i.e., shiny side) gave an improved flux performance of up to 53.6% and a decrease in specific energy of 35.4% compared to that by treating the membrane face with larger pores (i.e., dull side). The effect of the PDMS coating sequence also depended on the pore structure. For the face with smaller pore structures, coating PDMS before laser irradiation (PDMS-BLSS) gave a flux improvement of up to 24.5% and a decrease in specific energy of 19.7%, compared to coating PDMS after laser irradiation (PDMS-ALSS). As for the face with larger pore structures, coating PDMS before laser irradiation (PDMS-BLDS) resulted in a flux reduction of up to 20.8% and an increase in specific energy of 27.1%, compared to coating PDMS after irradiation (PDMS-ALDS). The LIG Janus membranes embedded with Ag nanoparticles led to improved photothermal heating properties, improving flux by 43.1-65.8% and decreasing specific energy by 15.2-30.5% while maintaining similar electrothermal heating properties. Carrying out simultaneous photo-and electro-thermal MD indicates that only the Ag-doped Janus LIG membrane gave a synergistic effect whereby the flux of the combined heating mode was higher than the summation of the fluxes obtained when operating in the individual heating modes.
Peatlands covers a vast area globally and used as drinking water source in some parts of Indonesi... more Peatlands covers a vast area globally and used as drinking water source in some parts of Indonesia. Peat water, commonly found in swampy areas, stands out for its striking color intensity, acidic pH levels, and its high affinity for metal binding. Developing various peat water treatment techniques can help provide clean water for local communities. This study reported the preparation of hydroxyapatite (HAp) via hydrothermal method using Carbon Negative Precipitated Calcium Carbonate (PCC) as precursor, obtained from PT. Pertamina, a leading energy company of Indonesia, for treating peat water. HAps were synthesized from precursors that were calcined at 900 • C (HAp 900) and 1000 • C (HAp 1000). Its potential as an adsorbent for peat water purification was evaluated. X-ray diffraction (XRD) revealed good crystallinity in HAp 900 and HAp 1000, with values of 82.33 % and 86.90 %, respectively. These samples also displayed nano-sized crystals, measuring 14.2 ± 0.3 nm and 23.80 ± 0.2 nm. The Ca/P molar ratios were 1.6 for HAp 900 and 1.57 for HAp 1000, which was close to the the theoretical hydroxyapatite ratio of 1.67. FTIR analysis detected the presence of carbonate groups at 1450.42 cm − 1 for HAp 900 and 1426 cm − 1 for HAp 1000, indicating the formation of carbonated hydroxyapatite. Scanning electron microscopy (SEM) revealed agglomerations and irregularly shaped particles in both HAp samples. Optimal conditions for peat water purification experiment, determined through UV-Vis spectrophotometry, were pH 2, 1 h contact time, and 1 g adsorbent mass for both HAp 900 and HAp 1000.
Photocatalysts are promising materials for removing organic dyes from the environment. TiO2 is on... more Photocatalysts are promising materials for removing organic dyes from the environment. TiO2 is one of the most extensively studied photocatalysts; however, its application in the photocatalytic industry has yet to be realized. We contend that fundamental research and the quest for synergy are essential in this field. One approach to enhancing the efficiency of TiO2 is deposition onto porous inert substrates. In this work, we introduce a novel approach by applying TiO2 onto the surfaces of porous nanosized Al 2 O 3 and ZrO2. Employing two soft chemistry methods-the glycol-citrate route for creating a porous and inert substrate and the peroxide route for depositing a TiO2 layer-we have created a technology that allows us to vary the TiO2 concentration on the inert matrix. The developed composite photocatalysts demonstrate competitive efficacy in disintegrating the model dye methylene blue. The most effective photocatalyst was Al2O3 @Ti 2 (0.26 wt.%) at 1200 °C. This material degrades approximately 98.2% of the methylene blue in 5 h, while nanosized TiO2 degrades only 33.5% of the dye under the same conditions. The photocatalytic activity of the material is affected by the concentration of TiO2 in the material due to the dilution of the peroxide solution. Notably, a decrease in the TiO2 concentration enhances the photocatalytic activity of the composite. We assumed that titanium dioxide was distributed in thinner layers at lower concentrations, which increased the area of effective contact and photocatalytic activity. The most efficient aluminum and zirconium oxides decorated with titanium dioxide had surface areas of 12.7 and 16.9 m 2 /g, respectively, while Al2 O3 and ZrO2 had surface areas of 31.7 and 34.3 m 2 /g, respectively. Therefore, the decrease in methylene blue concentration was caused by photocatalysis but not by the sorption mechanism. The decomposition of methylene blue in all the samples is consistent with a pseudo-second-order photocatalysis model. The findings of this work lie in the precise application of TiO2 onto the surfaces of inert matrices, which is valuable for developing photocatalytic materials.
Case Studies in Chemical and Environmental Engineering, 2024
This research explores utilizing abundant and economical cassava as a raw material for producing ... more This research explores utilizing abundant and economical cassava as a raw material for producing cationic starch in Indonesia. Cationic starch was synthesized by etherifying cassava starch with CHPTAC monomer at 50-90 • C. Successful cationic modification was confirmed via FTIR and NMR spectra. Characterization revealed the 80 • C product exhibited optimal properties: high degree of substitution (0.35) and reaction efficiency (98 ± 1.2 %). The amorphous form of the 80 • C product reduced its thermal resistance. This economically viable process uses readily available cassava to produce high-value cationic starch, currently an expensive imported product, demonstrating potential to enhance domestic production and reduce import reliance.
This review highlights Carbon Quantum Dots (CQDs) as promising photocatalysts for breaking down o... more This review highlights Carbon Quantum Dots (CQDs) as promising photocatalysts for breaking down organic pollutants, particularly in advancing CQDs-based systems for degrading organic dyes. CQDs, used alone or combined with semiconductors, enhance performance. In scenarios with narrow bandgaps, CQDs assist in separating charges, whereas in wider bandgaps, they enable visible/NIR activity through up-conversion luminescence. When integrated into Z-scheme heterostructures, CQDs reduce recombination by facilitating electron transfer. Synthesis methods-both top-down and bottom-up-are explored along with crucial physicochemical properties. Furthermore, modifying CQDs through doping and integrating functional groups on their surface adjusts their characteristics, promising more effective CQDs-modified photocatalysts in future research.
Boosting both the lightweight and rebound of a shoe's midsole without compromising its durability... more Boosting both the lightweight and rebound of a shoe's midsole without compromising its durability is regarded as a challenging aspect of developing excellent running shoes. This study explores the replacement of talc, a conventional reinforcing and nucleating agent for polymers, with multi-walled carbon nanotubes (MWCNTs) derived from plastics in the midsole foam of running shoes to enhance lightweight, rebound, and durability. Two types of MWCNTs, non-functionalized and oxygen-functionalized, derived from upcycling mixed plastics were processed with copolymer of ethyl-vinyl acetate (EVA) to create nanocomposite foams. The foam reinforced with non-functionalized MWCNTs exhibited higher dynamic stiffness and similar energy return to oxygenfunctionalized MWCNTs. The running shoe prototypes with EVA midsole foam containing 0.5 wt% MWCNTs was 13 % lighter and returned more than 10 % higher energy than the conventional EVA midsole foam with mineral fillers. Additionally, the midsole foam produced from EVA/MWCNTs demonstrated greater flexibility, and durability after 500 km of dynamic impact cycles. The cost difference per pair of running shoe midsole is merely 0.08 USD, considering the exceptional performance of the EVA/MWCNTs midsole as compared to conventional mineral filled EVA midsole. These findings indicate the potential for commercializing EVA/MWCNTs nanocomposite foam as a viable option for high-performance running shoe midsoles, offering athletes improved running performance.
Noble metal-based high entropy alloys (NM-HEAs) have been shown to have optimized catalytic prope... more Noble metal-based high entropy alloys (NM-HEAs) have been shown to have optimized catalytic properties through compositional adjustments. Recently, an amorphous HEA, known as high-entropy metallic glass (HEMG), has gained attention for its potential in surface modification and atomic rearrangement. In this work, RhRuPtPdIr HEA thin films (Rh : Ru : Pt : Pd : Ir = 26.1 : 28.7 : 8.6 : 16.3 : 20.3) were synthesized on glassy carbon (GC) electrodes using precisely controlled sequential atomic layer deposition (ALD) process of each noble metal layer, followed by electrical Joule heating (EJH) alloying at 1000 °C for 5 seconds. Cross-sectional HR-TEM imaging revealed a thickness of 20 nm and the surface microstructure composed of nanocrystallites and amorphous structures, suggesting explosive crystallization during the EJH process. The HEA thin film achieved outstanding HER performance, exhibiting overpotentials of 13, 77, and 65 mV at a current density of 10 mA cm−2 and Tafel slopes of 14, 45, and 78 mV dec−1 in 0.5 M H2SO4, 1.0 M PBS, and 1.0 M KOH electrolytes, respectively. Remarkably, HEA/GC in an acidic environment reached strikingly top-level kinetics, which was mainly contributed by intrinsic activity and surface amorphization. The corresponding DFT study revealed a modified electronic structure of the HEA surface that facilitates surface–hydrogen interaction. The study demonstrates the potential of NMHEA nanofilm as catalysts for highly efficient HER in harsh environments. This study also demonstrates that ALD-EJH is a novel and reliable method for synthesizing, manipulating, and tuning complex high entropy nanomaterials
This study aims to optimize the development process of bismuth oxide/carbon dots (Bi2O3/Cdots) us... more This study aims to optimize the development process of bismuth oxide/carbon dots (Bi2O3/Cdots) using microwave-assisted precipitation for antibiotics removal. Experimental design and analysis of optimum formulation predictions is conducted using the response surface methodology-central composite design (RSM-CCD). Analysis of variance (ANOVA) is used for model development and the fit optimized model is validated through actual experiments considering error estimation metrics. Optimal synthesis conditions is achieved by developing Bi2O3/Cdots 13.31%wt under 780 W microwaves for 17.35 minutes. The analysis of optical properties and crystallinity shows that the composite has a narrow bandgap compared to Bi2O3 with a lattice spacing of 0.32 nm. The morphological and topographical profiles shows that the composite structure consists of Bi2O3 rods with wavy, irregular, and rough surfaces decorated with colonies of Cdots. The chemical state of the composite consists of Bi, O, and C which are distributed throughout the surface with a lower binding energy compared to Bi2O3. Through disc diffusion, composite reduced the inhibition zone, which means it is able to reduce the antibacterial activity and antibiotic efficacy. The optimized composite is able to degrade 76.6% ciprofloxacin (CIP), 73.3% cefadroxil (CEF), 54.4% amoxicillin (AMX), and 60.3% mixed antibiotics (MIX). Our findings indicated that the developed Bi2O3/Cdots is capable of robust removal in various antibiotic pollutants.
Piezoelectric effect plays an important role in a variety of applications, such as sensors, nanog... more Piezoelectric effect plays an important role in a variety of applications, such as sensors, nanogenerators and piezotronics. The performance of piezoelectric device is normally enhanced with increasing dimension of the piezoelectric layer and decreasing piezoelectric layer thickness. To meet the demand for producing superior piezoelectric films (as thin as 1 nm) with precise thickness and composition control, powerful fabrication techniques are essential. Atomic layer deposition (ALD) shows exceptional potential in preparing a wide range of materials with precise thickness control (due to its self-limiting growth nature at the Angstrom level) and capability of deposition on high aspect ratio surface. Here, we provide the introduction to ALD and highlight its unique features among other fabrication techniques, with reference to the state of the art on ALD preparation of different piezoelectric materials, including novel transition metal dichalcogenides (TMDs) and traditional Metal Oxides (MOs). Different ALD-related materials preparation strategies for the improvement of piezoelectricity are also discussed, together with future perspectives on the development of ALD-prepared piezoelectric materials. We believe ALD can enable wider applications of piezoelectricity due to its unique advantages.
The influence of Cr on the interfacial bonding and erosion-corrosion resistance of ZrO 2-Al 2 O 3... more The influence of Cr on the interfacial bonding and erosion-corrosion resistance of ZrO 2-Al 2 O 3 particles reinforced high chromium white cast irons based (ZTA P /Fe) composites were systematically investigated. The Cr coatings on the surface of ZTA particle (ZTA P) ceramics were fabricated by multi-arc ion plating. The results indicated that a uniform and continuous Cr coating was tightly adhered with ZTA ceramic substrate. The thickness and grain size of the Cr coating could be effectively controlled by regulating the deposition parameters. The grain size of Cr coating increased with deposition time. The ZTA P /Fe composites assisted without (N1) and with (N2) Cr coating were prepared via infiltration casting. The addition of Cr coating obtained a smooth and tight interface, attributed to the improvement of the wettability between ZTA ceramic and high chromium white cast irons matrix (Cr15). Moreover, the erosion-corrosion resistance property of the Cr coated ZTA P /Fe composites (N2) improved up to 44% compared with bare-ZTA P /Fe composites (N1) due to their interfacial enhancement action. Meanwhile, the interfacial layer of the N2 composites had a low roughness after erosion-corrosion.
The current synthesis methods of high-entropy alloy (HEA) thinfilm coatings face huge challenges ... more The current synthesis methods of high-entropy alloy (HEA) thinfilm coatings face huge challenges in facile preparation, precise thickness control, conformal integration, and affordability. These challenges are more specific and noteworthy for noble metal-based HEA thin films where the conventional sputtering methods encounter thickness control and high-cost issues (high-purity noble metal targets required). Herein, for the first time, we report a facile and controllable synthesis process of quinary HEA coatings consisting of noble metals (Rh, Ru, Pt, Pd, and Ir), by sequential atomic layer deposition (ALD) coupled with electrical Joule heating for post-alloying. Furthermore, the resulting quinary HEA thin film with a thickness of ∼50 nm and an atomic ratio of 20:15:21:18:27 shows promising potential as a platform for catalysis, exhibiting enhanced electrocatalytic hydrogen evolution reaction (HER) performances with lower overpotentials (e.g., from 85 to 58 mV in 0.5 M H 2 SO 4) and higher stability (by retaining more than 92% of the initial current after 20 h with a current density of 10 mA/cm 2 in 0.5 M H2SO4) than other noble metal-based structure counterparts in this work. The enhanced material properties and device performances are attributed to the efficient electron transfer of HEA with the increased number of active sites. This work not only presents RhRuPtPdIr HEA thin films as promising HER catalysts but also sheds light on controllable fabrication of conformal HEA-coated complex structures toward a broad range of applications.
Abstract Zirconia-toughened alumina ceramic particle (ZTAP)-reinforced high Cr cast Fe matrix com... more Abstract Zirconia-toughened alumina ceramic particle (ZTAP)-reinforced high Cr cast Fe matrix composites (ZTAP/Fe composites) are promising advanced wear-resistant materials. However, due to wear and tear, the ceramic particles may shed from the Fe matrix because of their low interfacial bonding properties. In the present work, we investigated interfacial characteristics and abrasive wear behaviours of ZTAP/Fe composites. Results showed that sintering played a significant role in the formation of sintering necks and consequently affected both compressive strengths and porosities of ZTA ceramic preforms. Optimum compressive strength (44.3 MPa) and porosity (25.2%) were obtained when sintering was performed at 1350 °C for 1 h. Subsequently, ZTAP/Fe composites without evident defects were fabricated by infiltration casting. Scanning electron microscopy, electron probe microanalysis and transmission electron microscopy were also used to analyse the microstructures and phase constituents of the interfacial layers of composites. Effects of applied wear loads on the wear behaviour evolutions and wear mechanisms of composites were examined. Wear resistances of ZTAP/Fe composites were found to be 1.64–2.21 times as compared to the Cr15 specimen.
South African Journal of Chemical Engineering, 2024
Cationic particles are commonly used as wet-end additives in papermaking processes. This study ev... more Cationic particles are commonly used as wet-end additives in papermaking processes. This study evaluates the effects of cationic cassava starch (CCS) on the mechanical strength of paper made from bacterial cellulose (BC). Acetobacter xylinum was utilised in the production of bacterial cellulose (BC) paper, whereas 3-chloro-2hydroxypropyl trimethyl ammonium chloride (CHPTAC) was employed in the etherification process of cassava starch to synthesize CCS. Papers containing CCS displayed a more compact surface structure compared to traditional wood-based papers, reaching a brightness level of 97.3 and improving thermal and mechanical characteristics, such as higher tensile strength and is suitable for use as a separator in battery fabrication processes. The results emphasise the possibility of using CCS as a sustainable option in paper production, offering enhanced environmental and mechanical efficiency.
This study introduces a sustainable method of producing a graphene nano sheet (GNS) from coconut ... more This study introduces a sustainable method of producing a graphene nano sheet (GNS) from coconut shells and investigates its application in GNS, Ni/GNS, and Zn/GNS electrodes for advanced energy storage devices. The GNS was synthesized in a scalable manner using a pyrolysis and impregnation technique, with its successful synthesis verified by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and electrical conductivity measurement characterizations. The study highlights the enhanced performance of Zn/GNS electrodes, which outperform both pure GNS and Ni/GNS variants. This superior performance is attributed to the smaller particle size of Zn (mean = 2.356 μm) compared to Ni (mean = 3.09 μm) and Zn’s more favourable electron configuration for electron transfer. These findings demonstrate the potential of bio-derived GNS composites as efficient, high-performance electrodes, paving the way for more sustainable and cost-effective energy storage solutions.
This study employs a cost-efficient method to create a pliable BC/rGO-NiCo-LDH electrode film on ... more This study employs a cost-efficient method to create a pliable BC/rGO-NiCo-LDH electrode film on a bacterial cellulose base. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, Xray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) analyses verified the incorporation of reduced graphene oxide (rGO) and nickel-cobalt layered double hydroxide (NiCo-LDH) into the bacterial cellulose structure. The BC/rGO-NiCo-LDH composite material exhibited high-temperature stability and achieved a specific capacitance of 311 F g − 1 at a scan rate of 0.1 mV/s, surpassing that of earlier cellulose electrodes. The electrode film showed exceptional mechanical capabilities, displaying flexibility and load resistance without any structural damage. The film's flexibility and lightweight properties were improved due to the low density of 0.656 g cm − 3 , which is a result of the nanoporous structure and intrinsic low density of rGO and cellulose. A retention ratio of 0.40 for storage modulus at a glass transition temperature of around 90 • C demonstrated positive mechanical performance. This cost-effective and uncomplicated synthesis approach produced a BC/rGO-NiCo-LDH electrode with potential. The material possessed favourable mechanical and electrochemical characteristics, making it suitable for wearable electronics.
Graphene was synthesized through a two-step pyrolysis method using waste candlenut (Aleurites mol... more Graphene was synthesized through a two-step pyrolysis method using waste candlenut (Aleurites moluccanus) shells as the precursor. Cerium (Ce)/graphene composites were prepared via an impregnation technique. The resulting graphene and Ce/graphene were characterized using various analytical methods, including Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The bio-carbon produced predominantly exhibited a graphene structure with flat carbon morphology and an interlayer distance of 0.33 nm. This structural information is supported by XRD data, which shows a broad and weak peak at 2θ = 26◦ corresponding to the C (002) plane, indicative of graphene presence. FTIR, XPS, and Raman spectroscopy further confirmed the presence of graphene through the detection of Csp2 aromatic bonds and the characteristic D, G, and 2D peaks. Notably, the performance of cerium can be enhanced by the incorporation of graphene, attributed to the large surface area and chemical interactions between Ce and graphene. Consequently, candlenut-derived graphene shows potential as a supportive material for modifying the properties of cerium, due to the current value of Ce/Graphene increase with presence of graphene, thereby opening avenues for various advanced applications, such as sustainable and high-performance energy storage systems.
Case Studies in Chemical and Environmental Engineering, 2024
Biodegradable bioplastics provide a promising solution to mitigate environmental harm from petrol... more Biodegradable bioplastics provide a promising solution to mitigate environmental harm from petroleum-based plastics. This study focuses on optimizing bioplastic films made from oil palm trunk starch (OPTS), using glycerol (10, 20, and 30 % v/w) as a plasticizer and modified with citric-acid epoxidized palm oil (CEPO). The bioplastics were formed using the solution casting method and analyzed for morphology, functional groups, diffraction peaks, thermal and mechanical properties, degradation time, and compostability. The optimal conditions were achieved with 30 % glycerol (Sample ST-CEPO-GLY30). The addition of glycerol enhances the thermal and mechanical properties, improves the biodegradability, and compostability of the bioplastics.
This study investigated the potential of porous silica material extracted from volcanic ash of Mo... more This study investigated the potential of porous silica material extracted from volcanic ash of Mount Sinabung, Indonesia, as a corrosion inhibitor. The new material was subjected to comprehensive analysis using the X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Search Engine Marketing (SEM), and Atomic Absorption Spectrophotometry (AAS). Corrosion test was conducted by coating the metal surface with synthesized silica. XRD data showed the presence of amorphous silica, while SEM indicated a rough and irregular pore cavity. Based on AAS characterization, the concentration of silica in the Mount Sinabung volcanic ash was 79.23 % (v/v) with a yield of 29.73 %(w/w). Furthermore, coated and uncoated iron plates, with grit variations of 800, 1200, 1500, and 2000, were tested against HCl 15 % (v /v) and NaCl 3.5 % (w /v) as model corrosive solutions. The SEM results showed that coated plates had fewer holes and cracks formation while the XRD analysis of the same samples presented a slight decrease in the intensity of iron phase. Among silica-coated iron plates, the 1500 grit variation had the lowest corrosion rate and the highest corrosion inhibitor efficiency in both HCl 15 % (v /v) and NaCl 3.5 % (w /v) corrosive solutions, recording efficiencies of 26.3 and 91.8 %, respectively.
To optimize the Laser-Induced Graphene (LIG) Janus membrane, this study investigated the effects ... more To optimize the Laser-Induced Graphene (LIG) Janus membrane, this study investigated the effects of membrane pore structure, polydimethylsiloxane (PDMS) coating sequence and addition of silver (Ag) nanoparticles on membrane distillation (MD) performance. This study aimed to enhance the photothermal characteristics of graphene while using the intrinsic electrical conductivity for simultaneous photo-and electrothermal MD. Operating at the same photo-and electro-thermal power input, the LIG Janus membrane made by treating the membrane face with smaller pores (i.e., shiny side) gave an improved flux performance of up to 53.6% and a decrease in specific energy of 35.4% compared to that by treating the membrane face with larger pores (i.e., dull side). The effect of the PDMS coating sequence also depended on the pore structure. For the face with smaller pore structures, coating PDMS before laser irradiation (PDMS-BLSS) gave a flux improvement of up to 24.5% and a decrease in specific energy of 19.7%, compared to coating PDMS after laser irradiation (PDMS-ALSS). As for the face with larger pore structures, coating PDMS before laser irradiation (PDMS-BLDS) resulted in a flux reduction of up to 20.8% and an increase in specific energy of 27.1%, compared to coating PDMS after irradiation (PDMS-ALDS). The LIG Janus membranes embedded with Ag nanoparticles led to improved photothermal heating properties, improving flux by 43.1-65.8% and decreasing specific energy by 15.2-30.5% while maintaining similar electrothermal heating properties. Carrying out simultaneous photo-and electro-thermal MD indicates that only the Ag-doped Janus LIG membrane gave a synergistic effect whereby the flux of the combined heating mode was higher than the summation of the fluxes obtained when operating in the individual heating modes.
Peatlands covers a vast area globally and used as drinking water source in some parts of Indonesi... more Peatlands covers a vast area globally and used as drinking water source in some parts of Indonesia. Peat water, commonly found in swampy areas, stands out for its striking color intensity, acidic pH levels, and its high affinity for metal binding. Developing various peat water treatment techniques can help provide clean water for local communities. This study reported the preparation of hydroxyapatite (HAp) via hydrothermal method using Carbon Negative Precipitated Calcium Carbonate (PCC) as precursor, obtained from PT. Pertamina, a leading energy company of Indonesia, for treating peat water. HAps were synthesized from precursors that were calcined at 900 • C (HAp 900) and 1000 • C (HAp 1000). Its potential as an adsorbent for peat water purification was evaluated. X-ray diffraction (XRD) revealed good crystallinity in HAp 900 and HAp 1000, with values of 82.33 % and 86.90 %, respectively. These samples also displayed nano-sized crystals, measuring 14.2 ± 0.3 nm and 23.80 ± 0.2 nm. The Ca/P molar ratios were 1.6 for HAp 900 and 1.57 for HAp 1000, which was close to the the theoretical hydroxyapatite ratio of 1.67. FTIR analysis detected the presence of carbonate groups at 1450.42 cm − 1 for HAp 900 and 1426 cm − 1 for HAp 1000, indicating the formation of carbonated hydroxyapatite. Scanning electron microscopy (SEM) revealed agglomerations and irregularly shaped particles in both HAp samples. Optimal conditions for peat water purification experiment, determined through UV-Vis spectrophotometry, were pH 2, 1 h contact time, and 1 g adsorbent mass for both HAp 900 and HAp 1000.
Photocatalysts are promising materials for removing organic dyes from the environment. TiO2 is on... more Photocatalysts are promising materials for removing organic dyes from the environment. TiO2 is one of the most extensively studied photocatalysts; however, its application in the photocatalytic industry has yet to be realized. We contend that fundamental research and the quest for synergy are essential in this field. One approach to enhancing the efficiency of TiO2 is deposition onto porous inert substrates. In this work, we introduce a novel approach by applying TiO2 onto the surfaces of porous nanosized Al 2 O 3 and ZrO2. Employing two soft chemistry methods-the glycol-citrate route for creating a porous and inert substrate and the peroxide route for depositing a TiO2 layer-we have created a technology that allows us to vary the TiO2 concentration on the inert matrix. The developed composite photocatalysts demonstrate competitive efficacy in disintegrating the model dye methylene blue. The most effective photocatalyst was Al2O3 @Ti 2 (0.26 wt.%) at 1200 °C. This material degrades approximately 98.2% of the methylene blue in 5 h, while nanosized TiO2 degrades only 33.5% of the dye under the same conditions. The photocatalytic activity of the material is affected by the concentration of TiO2 in the material due to the dilution of the peroxide solution. Notably, a decrease in the TiO2 concentration enhances the photocatalytic activity of the composite. We assumed that titanium dioxide was distributed in thinner layers at lower concentrations, which increased the area of effective contact and photocatalytic activity. The most efficient aluminum and zirconium oxides decorated with titanium dioxide had surface areas of 12.7 and 16.9 m 2 /g, respectively, while Al2 O3 and ZrO2 had surface areas of 31.7 and 34.3 m 2 /g, respectively. Therefore, the decrease in methylene blue concentration was caused by photocatalysis but not by the sorption mechanism. The decomposition of methylene blue in all the samples is consistent with a pseudo-second-order photocatalysis model. The findings of this work lie in the precise application of TiO2 onto the surfaces of inert matrices, which is valuable for developing photocatalytic materials.
Case Studies in Chemical and Environmental Engineering, 2024
This research explores utilizing abundant and economical cassava as a raw material for producing ... more This research explores utilizing abundant and economical cassava as a raw material for producing cationic starch in Indonesia. Cationic starch was synthesized by etherifying cassava starch with CHPTAC monomer at 50-90 • C. Successful cationic modification was confirmed via FTIR and NMR spectra. Characterization revealed the 80 • C product exhibited optimal properties: high degree of substitution (0.35) and reaction efficiency (98 ± 1.2 %). The amorphous form of the 80 • C product reduced its thermal resistance. This economically viable process uses readily available cassava to produce high-value cationic starch, currently an expensive imported product, demonstrating potential to enhance domestic production and reduce import reliance.
This review highlights Carbon Quantum Dots (CQDs) as promising photocatalysts for breaking down o... more This review highlights Carbon Quantum Dots (CQDs) as promising photocatalysts for breaking down organic pollutants, particularly in advancing CQDs-based systems for degrading organic dyes. CQDs, used alone or combined with semiconductors, enhance performance. In scenarios with narrow bandgaps, CQDs assist in separating charges, whereas in wider bandgaps, they enable visible/NIR activity through up-conversion luminescence. When integrated into Z-scheme heterostructures, CQDs reduce recombination by facilitating electron transfer. Synthesis methods-both top-down and bottom-up-are explored along with crucial physicochemical properties. Furthermore, modifying CQDs through doping and integrating functional groups on their surface adjusts their characteristics, promising more effective CQDs-modified photocatalysts in future research.
Boosting both the lightweight and rebound of a shoe's midsole without compromising its durability... more Boosting both the lightweight and rebound of a shoe's midsole without compromising its durability is regarded as a challenging aspect of developing excellent running shoes. This study explores the replacement of talc, a conventional reinforcing and nucleating agent for polymers, with multi-walled carbon nanotubes (MWCNTs) derived from plastics in the midsole foam of running shoes to enhance lightweight, rebound, and durability. Two types of MWCNTs, non-functionalized and oxygen-functionalized, derived from upcycling mixed plastics were processed with copolymer of ethyl-vinyl acetate (EVA) to create nanocomposite foams. The foam reinforced with non-functionalized MWCNTs exhibited higher dynamic stiffness and similar energy return to oxygenfunctionalized MWCNTs. The running shoe prototypes with EVA midsole foam containing 0.5 wt% MWCNTs was 13 % lighter and returned more than 10 % higher energy than the conventional EVA midsole foam with mineral fillers. Additionally, the midsole foam produced from EVA/MWCNTs demonstrated greater flexibility, and durability after 500 km of dynamic impact cycles. The cost difference per pair of running shoe midsole is merely 0.08 USD, considering the exceptional performance of the EVA/MWCNTs midsole as compared to conventional mineral filled EVA midsole. These findings indicate the potential for commercializing EVA/MWCNTs nanocomposite foam as a viable option for high-performance running shoe midsoles, offering athletes improved running performance.
Noble metal-based high entropy alloys (NM-HEAs) have been shown to have optimized catalytic prope... more Noble metal-based high entropy alloys (NM-HEAs) have been shown to have optimized catalytic properties through compositional adjustments. Recently, an amorphous HEA, known as high-entropy metallic glass (HEMG), has gained attention for its potential in surface modification and atomic rearrangement. In this work, RhRuPtPdIr HEA thin films (Rh : Ru : Pt : Pd : Ir = 26.1 : 28.7 : 8.6 : 16.3 : 20.3) were synthesized on glassy carbon (GC) electrodes using precisely controlled sequential atomic layer deposition (ALD) process of each noble metal layer, followed by electrical Joule heating (EJH) alloying at 1000 °C for 5 seconds. Cross-sectional HR-TEM imaging revealed a thickness of 20 nm and the surface microstructure composed of nanocrystallites and amorphous structures, suggesting explosive crystallization during the EJH process. The HEA thin film achieved outstanding HER performance, exhibiting overpotentials of 13, 77, and 65 mV at a current density of 10 mA cm−2 and Tafel slopes of 14, 45, and 78 mV dec−1 in 0.5 M H2SO4, 1.0 M PBS, and 1.0 M KOH electrolytes, respectively. Remarkably, HEA/GC in an acidic environment reached strikingly top-level kinetics, which was mainly contributed by intrinsic activity and surface amorphization. The corresponding DFT study revealed a modified electronic structure of the HEA surface that facilitates surface–hydrogen interaction. The study demonstrates the potential of NMHEA nanofilm as catalysts for highly efficient HER in harsh environments. This study also demonstrates that ALD-EJH is a novel and reliable method for synthesizing, manipulating, and tuning complex high entropy nanomaterials
This study aims to optimize the development process of bismuth oxide/carbon dots (Bi2O3/Cdots) us... more This study aims to optimize the development process of bismuth oxide/carbon dots (Bi2O3/Cdots) using microwave-assisted precipitation for antibiotics removal. Experimental design and analysis of optimum formulation predictions is conducted using the response surface methodology-central composite design (RSM-CCD). Analysis of variance (ANOVA) is used for model development and the fit optimized model is validated through actual experiments considering error estimation metrics. Optimal synthesis conditions is achieved by developing Bi2O3/Cdots 13.31%wt under 780 W microwaves for 17.35 minutes. The analysis of optical properties and crystallinity shows that the composite has a narrow bandgap compared to Bi2O3 with a lattice spacing of 0.32 nm. The morphological and topographical profiles shows that the composite structure consists of Bi2O3 rods with wavy, irregular, and rough surfaces decorated with colonies of Cdots. The chemical state of the composite consists of Bi, O, and C which are distributed throughout the surface with a lower binding energy compared to Bi2O3. Through disc diffusion, composite reduced the inhibition zone, which means it is able to reduce the antibacterial activity and antibiotic efficacy. The optimized composite is able to degrade 76.6% ciprofloxacin (CIP), 73.3% cefadroxil (CEF), 54.4% amoxicillin (AMX), and 60.3% mixed antibiotics (MIX). Our findings indicated that the developed Bi2O3/Cdots is capable of robust removal in various antibiotic pollutants.
Piezoelectric effect plays an important role in a variety of applications, such as sensors, nanog... more Piezoelectric effect plays an important role in a variety of applications, such as sensors, nanogenerators and piezotronics. The performance of piezoelectric device is normally enhanced with increasing dimension of the piezoelectric layer and decreasing piezoelectric layer thickness. To meet the demand for producing superior piezoelectric films (as thin as 1 nm) with precise thickness and composition control, powerful fabrication techniques are essential. Atomic layer deposition (ALD) shows exceptional potential in preparing a wide range of materials with precise thickness control (due to its self-limiting growth nature at the Angstrom level) and capability of deposition on high aspect ratio surface. Here, we provide the introduction to ALD and highlight its unique features among other fabrication techniques, with reference to the state of the art on ALD preparation of different piezoelectric materials, including novel transition metal dichalcogenides (TMDs) and traditional Metal Oxides (MOs). Different ALD-related materials preparation strategies for the improvement of piezoelectricity are also discussed, together with future perspectives on the development of ALD-prepared piezoelectric materials. We believe ALD can enable wider applications of piezoelectricity due to its unique advantages.
The influence of Cr on the interfacial bonding and erosion-corrosion resistance of ZrO 2-Al 2 O 3... more The influence of Cr on the interfacial bonding and erosion-corrosion resistance of ZrO 2-Al 2 O 3 particles reinforced high chromium white cast irons based (ZTA P /Fe) composites were systematically investigated. The Cr coatings on the surface of ZTA particle (ZTA P) ceramics were fabricated by multi-arc ion plating. The results indicated that a uniform and continuous Cr coating was tightly adhered with ZTA ceramic substrate. The thickness and grain size of the Cr coating could be effectively controlled by regulating the deposition parameters. The grain size of Cr coating increased with deposition time. The ZTA P /Fe composites assisted without (N1) and with (N2) Cr coating were prepared via infiltration casting. The addition of Cr coating obtained a smooth and tight interface, attributed to the improvement of the wettability between ZTA ceramic and high chromium white cast irons matrix (Cr15). Moreover, the erosion-corrosion resistance property of the Cr coated ZTA P /Fe composites (N2) improved up to 44% compared with bare-ZTA P /Fe composites (N1) due to their interfacial enhancement action. Meanwhile, the interfacial layer of the N2 composites had a low roughness after erosion-corrosion.
The current synthesis methods of high-entropy alloy (HEA) thinfilm coatings face huge challenges ... more The current synthesis methods of high-entropy alloy (HEA) thinfilm coatings face huge challenges in facile preparation, precise thickness control, conformal integration, and affordability. These challenges are more specific and noteworthy for noble metal-based HEA thin films where the conventional sputtering methods encounter thickness control and high-cost issues (high-purity noble metal targets required). Herein, for the first time, we report a facile and controllable synthesis process of quinary HEA coatings consisting of noble metals (Rh, Ru, Pt, Pd, and Ir), by sequential atomic layer deposition (ALD) coupled with electrical Joule heating for post-alloying. Furthermore, the resulting quinary HEA thin film with a thickness of ∼50 nm and an atomic ratio of 20:15:21:18:27 shows promising potential as a platform for catalysis, exhibiting enhanced electrocatalytic hydrogen evolution reaction (HER) performances with lower overpotentials (e.g., from 85 to 58 mV in 0.5 M H 2 SO 4) and higher stability (by retaining more than 92% of the initial current after 20 h with a current density of 10 mA/cm 2 in 0.5 M H2SO4) than other noble metal-based structure counterparts in this work. The enhanced material properties and device performances are attributed to the efficient electron transfer of HEA with the increased number of active sites. This work not only presents RhRuPtPdIr HEA thin films as promising HER catalysts but also sheds light on controllable fabrication of conformal HEA-coated complex structures toward a broad range of applications.
Abstract Zirconia-toughened alumina ceramic particle (ZTAP)-reinforced high Cr cast Fe matrix com... more Abstract Zirconia-toughened alumina ceramic particle (ZTAP)-reinforced high Cr cast Fe matrix composites (ZTAP/Fe composites) are promising advanced wear-resistant materials. However, due to wear and tear, the ceramic particles may shed from the Fe matrix because of their low interfacial bonding properties. In the present work, we investigated interfacial characteristics and abrasive wear behaviours of ZTAP/Fe composites. Results showed that sintering played a significant role in the formation of sintering necks and consequently affected both compressive strengths and porosities of ZTA ceramic preforms. Optimum compressive strength (44.3 MPa) and porosity (25.2%) were obtained when sintering was performed at 1350 °C for 1 h. Subsequently, ZTAP/Fe composites without evident defects were fabricated by infiltration casting. Scanning electron microscopy, electron probe microanalysis and transmission electron microscopy were also used to analyse the microstructures and phase constituents of the interfacial layers of composites. Effects of applied wear loads on the wear behaviour evolutions and wear mechanisms of composites were examined. Wear resistances of ZTAP/Fe composites were found to be 1.64–2.21 times as compared to the Cr15 specimen.
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Papers by Ronn Goei
and impregnation technique, with its successful synthesis verified by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and electrical conductivity measurement
characterizations. The study highlights the enhanced performance of Zn/GNS electrodes, which outperform both pure GNS and Ni/GNS variants. This superior performance is attributed to the smaller particle size of Zn (mean = 2.356 μm) compared to Ni (mean = 3.09 μm) and Zn’s more
favourable electron configuration for electron transfer. These findings demonstrate the potential of bio-derived GNS composites as efficient, high-performance electrodes, paving the way for more sustainable and cost-effective energy storage solutions.
various analytical methods, including Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission
Electron Microscopy (TEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The bio-carbon produced
predominantly exhibited a graphene structure with flat carbon morphology and an interlayer distance of 0.33 nm. This structural information is supported by XRD data, which shows a broad and weak peak at 2θ = 26◦ corresponding to the C (002) plane, indicative of graphene presence. FTIR,
XPS, and Raman spectroscopy further confirmed the presence of graphene through the detection of Csp2 aromatic bonds and the characteristic D, G, and 2D peaks. Notably, the performance of cerium can be enhanced by the incorporation of graphene, attributed to the large surface area and chemical interactions between Ce and graphene. Consequently, candlenut-derived graphene shows potential as a supportive material for modifying the properties of cerium, due to the current value of Ce/Graphene increase with presence of graphene, thereby opening avenues for various advanced
applications, such as sustainable and high-performance energy storage systems.
(HEMG), has gained attention for its potential in surface modification and atomic rearrangement. In this work, RhRuPtPdIr HEA thin films (Rh : Ru : Pt : Pd : Ir = 26.1 : 28.7 : 8.6 : 16.3 : 20.3) were synthesized on glassy carbon (GC) electrodes using precisely controlled sequential atomic layer deposition (ALD) process of each noble metal layer, followed by electrical Joule heating (EJH) alloying at 1000 °C for 5 seconds. Cross-sectional HR-TEM imaging revealed a thickness of 20 nm and the surface microstructure composed of nanocrystallites and amorphous structures, suggesting explosive crystallization during the
EJH process. The HEA thin film achieved outstanding HER performance, exhibiting overpotentials of 13, 77, and 65 mV at a current density of 10 mA cm−2 and Tafel slopes of 14, 45, and 78 mV dec−1 in 0.5 M
H2SO4, 1.0 M PBS, and 1.0 M KOH electrolytes, respectively. Remarkably, HEA/GC in an acidic environment reached strikingly top-level kinetics, which was mainly contributed by intrinsic activity and surface amorphization. The corresponding DFT study revealed a modified electronic structure of the HEA surface that facilitates surface–hydrogen interaction. The study demonstrates the potential of NMHEA nanofilm as catalysts for highly efficient HER in harsh environments. This study also demonstrates that ALD-EJH is a novel and reliable method for synthesizing, manipulating, and tuning complex high entropy nanomaterials
consists of Bi, O, and C which are distributed throughout the surface with a lower binding energy compared to Bi2O3. Through disc diffusion, composite reduced the inhibition zone, which means it is able to reduce the antibacterial activity and antibiotic efficacy. The optimized composite is able to degrade 76.6% ciprofloxacin (CIP), 73.3% cefadroxil (CEF), 54.4% amoxicillin (AMX), and 60.3% mixed antibiotics (MIX). Our findings
indicated that the developed Bi2O3/Cdots is capable of robust removal in various antibiotic pollutants.
and impregnation technique, with its successful synthesis verified by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and electrical conductivity measurement
characterizations. The study highlights the enhanced performance of Zn/GNS electrodes, which outperform both pure GNS and Ni/GNS variants. This superior performance is attributed to the smaller particle size of Zn (mean = 2.356 μm) compared to Ni (mean = 3.09 μm) and Zn’s more
favourable electron configuration for electron transfer. These findings demonstrate the potential of bio-derived GNS composites as efficient, high-performance electrodes, paving the way for more sustainable and cost-effective energy storage solutions.
various analytical methods, including Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission
Electron Microscopy (TEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The bio-carbon produced
predominantly exhibited a graphene structure with flat carbon morphology and an interlayer distance of 0.33 nm. This structural information is supported by XRD data, which shows a broad and weak peak at 2θ = 26◦ corresponding to the C (002) plane, indicative of graphene presence. FTIR,
XPS, and Raman spectroscopy further confirmed the presence of graphene through the detection of Csp2 aromatic bonds and the characteristic D, G, and 2D peaks. Notably, the performance of cerium can be enhanced by the incorporation of graphene, attributed to the large surface area and chemical interactions between Ce and graphene. Consequently, candlenut-derived graphene shows potential as a supportive material for modifying the properties of cerium, due to the current value of Ce/Graphene increase with presence of graphene, thereby opening avenues for various advanced
applications, such as sustainable and high-performance energy storage systems.
(HEMG), has gained attention for its potential in surface modification and atomic rearrangement. In this work, RhRuPtPdIr HEA thin films (Rh : Ru : Pt : Pd : Ir = 26.1 : 28.7 : 8.6 : 16.3 : 20.3) were synthesized on glassy carbon (GC) electrodes using precisely controlled sequential atomic layer deposition (ALD) process of each noble metal layer, followed by electrical Joule heating (EJH) alloying at 1000 °C for 5 seconds. Cross-sectional HR-TEM imaging revealed a thickness of 20 nm and the surface microstructure composed of nanocrystallites and amorphous structures, suggesting explosive crystallization during the
EJH process. The HEA thin film achieved outstanding HER performance, exhibiting overpotentials of 13, 77, and 65 mV at a current density of 10 mA cm−2 and Tafel slopes of 14, 45, and 78 mV dec−1 in 0.5 M
H2SO4, 1.0 M PBS, and 1.0 M KOH electrolytes, respectively. Remarkably, HEA/GC in an acidic environment reached strikingly top-level kinetics, which was mainly contributed by intrinsic activity and surface amorphization. The corresponding DFT study revealed a modified electronic structure of the HEA surface that facilitates surface–hydrogen interaction. The study demonstrates the potential of NMHEA nanofilm as catalysts for highly efficient HER in harsh environments. This study also demonstrates that ALD-EJH is a novel and reliable method for synthesizing, manipulating, and tuning complex high entropy nanomaterials
consists of Bi, O, and C which are distributed throughout the surface with a lower binding energy compared to Bi2O3. Through disc diffusion, composite reduced the inhibition zone, which means it is able to reduce the antibacterial activity and antibiotic efficacy. The optimized composite is able to degrade 76.6% ciprofloxacin (CIP), 73.3% cefadroxil (CEF), 54.4% amoxicillin (AMX), and 60.3% mixed antibiotics (MIX). Our findings
indicated that the developed Bi2O3/Cdots is capable of robust removal in various antibiotic pollutants.