Kee Shyuan Loh

• Doctor of Philosophy (Chemistry)
• Senior Researcher at National University of Malaysia

This study investigates the effects of crosslinking strategies and KOH activation on the multifaceted characteristics of quaternized poly(vinyl alcohol) (QPVA) membranes for anion exchange membrane (AEM) applications. In situ and combined in situ/ex situ crosslinking with glutaraldehyde were evaluated at 5 M, 6 M, and 8 M KOH concentrations. Multif...

The generation of hydrogen gas through microbial electrolysis (MEC), which is one of the bioelectrochemical system (BES) approaches, has been extensively explored in recent years. The biohydrogen produced in this process is considered green hydrogen and thus is an alternative to other conventional methods that mostly produce blue or gray hydrogen w...

Nafion is a commercial polymer membrane that is commonly used in fuel cell systems, despite its major limitations such as high fuel crossover and high manufacture cost. The production of sodium alginate (SA) blended membrane with crosslinking agent (glutaraldehyde) and plasticizer (glycerol) is one of several current efforts to discover an alternat...

The alkaline fuel cell is subject to extensive research owing to its fast kinetic response relative to acidic media. However, the efficiency of the catalytic layer at the electrodes depends on the amount and distribution of ionomers present there. It is crucial to have the right ionomer concentration to have the best cell performance. Additionally,...

The polybenzimidazole (PBI) membrane shows significant potential as an alternative membrane for high-temperature PEMFC. However, PBI membranes exhibit low proton conductivities under low humidity conditions and have drawbacks related to acid leaking and phosphoric acid degradation over 160°C. Notably, metal oxide particles exhibit a strong affinity...

The utilization of anion exchange membranes (AEMs) has revolutionized the field of electrochemical applications, particularly in water electrolysis and fuel cells. This review paper provides a comprehensive analysis of recent studies conducted on various commercial AEMs, including FAA3-50, Sustainion, Aemion™, XION Composite, and PiperION™ membrane...

Microbial electrosynthesis (MES) is an emerging electrochemical technology currently being researched as a CO2 sequestration method to address climate change. MES can convert CO2 from pollution or waste materials into various carbon compounds with low energy requirements using electrogenic microbes as biocatalysts. However, the critical component i...

The development of nonnoble metal oxygen reduction reaction (ORR) catalysts for fuel cells has been motivated by the high cost and limited supply of noble metals, as well as the desire to improve the performance and durability of this type of energy conversion device. In this study, nonnoble Fe–N–C catalyst was synthesized using a zeolitic imidazol...

Metal–organic frameworks (MOFs) are porous crystalline materials with exceptional properties. The tremendous synthetic tunability of MOFs has emerged to be beneficial for many applications. This review study discusses the roles of MOFs in hydrogen fuel cell technology, including the synthesis of oxygen reduction catalysts, hydrogen storage material...

Sluggish oxygen reduction reaction (ORR) of electrodes is one of the main challenges in fuel cell systems. This study explored the kinetics of the ORR reaction mechanism, which enables us to understand clearly the electrochemical activity of the electrode. In this research, electrocatalysts were synthesized from platinum (Pt) catalyst with multi-wa...

This work aims to encourage the use of natural materials for advanced energy applications, such as proton exchange membranes in fuel cells. Herein, a new conductive membrane produced from cassava liquid waste was used to overcome environmental pollution and the global crisis of energy. The membrane was phosphorylated through a microwave-assisted me...

Green hydrogen production via electrocatalytic water splitting paves the way for renewable, clean, and sustainable hydrogen (H2) generation. H2 gas is produced from the cathodic hydrogen evolution reaction (HER), where the reaction is catalyzed primarily from Pt-based catalysts under both acidic and alkaline environments. Lowering the loading of Pt...

Platinum (Pt) supported on carbon has been used as a state-of-the-art material as an electrocatalyst in proton exchange membrane fuel cells (PEMFCs). Nonetheless, the carbon corrosion issues that occur during fuel cell operations shorten the electrode lifespan. More corrosive resistance carbon-free materials with a high electrical conductivity have...

In our previous work, phosphorylated chitosan was modified through polymer blending with poly(vinyl alcohol) (PVA) polymer to produce N-methylene phosphonic chitosan/poly(vinyl alcohol) (NMPC/PVA) composite membranes. The aim of this work is to further investigate the effects of a propylammonium nitrate (PAN) ionic liquid and/or silicon dioxide (Si...

The performance of supercapacitors (SC) strongly depends on how their activated carbon (AC) electrodes were synthesized from precursor materials and pretreatments applied to them. This study investigates the effect of direct and filtered gamma radiations applied as pretreatments to the AC. The exposure doses used were from 0.1 kGy to 6 kGy. The hig...

The biocathode in a microbial fuel cell (MFC) system is a promising and a cheap alternative method to improve cathode reaction performance. This study aims to identify the effect of the electrode combination between non-chemical modified stainless steel (SS) and graphite fibre brush (GFB) for constructing bio-electrodes in an MFC. In this study, th...

The development of protic ionic liquids (PILs) in proton exchange membrane has drawn significant interest. The intrinsic properties of high thermal stability and proton conductivity of PILs at high temperature (> 100 °C) enables fuel cell operation at anhydrous condition. This review discusses the roles of PILs in different types of polymeric membr...

Bio-nanosilica (bio-SiO2) from rice husk ash (RHA) has attracted interest as a sustainable material that can be used as a catalyst support for various applications. Pt supported on bio-SiO2 (Pt/SiO2) shows the potential for application as a non-carbon based support for fuel cell catalysts. In this work, bio-SiO2 and Pt/SiO2 were synthesized, and th...

Bacterial cellulose, BC is a natural compound that produced by bacteria Acetobacter xylinum in static or agitated cultures. BC has excellent properties such as excellent mechanical properties, high crystallinity, high purity, high water holding capacity and high permeability for water vapour and gases. Based on this unique and extraordinary propert...

Anion exchange membrane water electrolyzer (AEMWE) is a promising technology in water electrolysis for the production of green hydrogen. Unlike conventional alkaline water electrolyzers (AWE), AEMWEs utilize mild alkaline conditions and anion exchange membranes as separators and ionic conductors, respectively. However, the largest merit of AEMWE is...

Increasing world energy demand and the rapid depletion of fossil fuels has initiated explorations for sustainable and green energy sources. High-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are viewed as promising materials in fuel cell technology due to several advantages, namely improved kinetic of both electrodes, higher toler...

Chitosan is one of the natural biopolymers that has been studied as an alternative material to replace Nafion membranes as proton change membranes. Nevertheless, unmodified chitosan membranes have limitations including low proton conductivity and mechanical stability. The aim of this work is to study the effect of modifying chitosan through polymer...

Electrolysis coupled with renewable energy resources is the most promising method for green hydrogen production. Polymer electrolyte membrane water electrolyzer (PEMWE) has attracted attention due to its ability to produce high‐purity, compressed hydrogen at relatively mild operating temperatures (70°C‐90°C). The highest cost contributor of the PEM...

The study aimed to obtain a chitosan/sulfonated poly(vinyl alcohol) (CS/SPVA) membrane with optimised hydrolytic stability and ion conduction properties by using the Taguchi method. Three factor variables including concentration of glutaraldehyde (GA), crosslinking temperature and crosslinking time were considered. An L18 orthogonal array along wit...

Pyrolysed Fe-N-C catalysts are foreseen to be promising noble-free cathode catalysts for proton exchange membrane fuel cells. Nevertheless, efforts are required to overcome active site degradation, which is influenced by the meso/macroporous composition of the catalyst and support. Reduced graphene oxide from Sengon wood is seen as a potential supp...

The oxygen reduction reaction (ORR) that occurs in the cathode of fuel cells is a major issue in proton exchange membrane fuel cells (PEMFCs) due to their sluggish kinetics. Exploring suitable materials for use as cathode catalysts can be challenging because the materials should be chemically active yet must be stable in an extremely corrosive envi...

The polymer electrolyte membrane (PEM) is a key component in the PEM fuel cell (PEMFC) system. This study highlights the latest development of PEM technology by combining Nafion® and ionic liquids, namely 2–Hydroxyethylammonium Formate (2–HEAF) and Propylammonium Nitrate (PAN). Test membranes were prepared using the casting technique. The impact of...

This review discusses the roles of anion exchange membrane (AEM) as a solid-state electrolyte in fuel cell and electrolyzer applications. It highlights the advancement of existing fabrication methods and emphasizes the importance of radiation grafting methods in improving the properties of AEM. The development of AEM has been focused on the improve...

The cost of conventional membrane, Nafion® used in the current proton exchange membrane fuel cell (PEMFC) is high. Thus different alternatives are being proposed as an option of Nafion® membrane in PEMFC application. In this study, poly(vinyl alcohol)/ N-methylene phosphonic chitosan/ 2-hydroxyethylammonium formate (PVA/NMPC/2-HEAF) proton exchange...

Polybenzimidazole (PBI) nanofiber membranes were prepared using electrospinning potential of 15 kV and 0.2 ml/h flow rate at different PBI concentrations (6.5 and 7.5 w/v%) with the solvent mixture ratio (DMAc:DMF) of 1:1 and 2:1, respectively. This study investigated the properties of the polymeric solution and the effects of solvent ratio and con...

Heteroatom-doped carbon materials with hierarchical porous structures are promising alternatives to replace the use of scarce platinum catalysts in fuel cells for oxygen reduction reaction (ORR). In this work, nitrogen-doped hierarchical porous carbon is developed from abundantly available textile waste activated with calcium chloride as the pore f...

The physical and proton conduction properties of electrolyte membranes are crucial for the development of proton-exchange membrane fuel cells (PEMFCs). However, data on novel bulk polymers is lacking, which is detrimental to conveying their superiority for applications. Hence, molecular dynamics (MD) simulations could lead to understanding some imp...

Aluminum alloy 5052 (AA5052) contains Mg (2.2-2.8.8% weight), Cu (0.1% weight), Cr (0.15% weight), Zn (0.1% weight), Si and Fe (0.45% weight) compositions. This material has been widely used as a bipolar plate in Proton exchange Membrane (PEMFC) fuel cells. This material has several advantages such as: lightness, high conductivity, good tensile str...

h i g h l i g h t s Catalyst supporting materials were synthesized by solution processing methods. Polymer/MWCNT nano-composites considerably enhanced in the BET surface area. MWCNT/PBI/Pt electrocatalyst exhibits higher catalytic activity and constancy. Nanocomposite Multi-walled carbon nanotube Electrocatalyst PEM fuel Cell a b s t r a c t In thi...

This work aims to study the effect of using sulfosuccinic acid (SSA) and 4-sulfophthalic acid (SPTA) to crosslink the chitosan/poly(vinyl)alcohol (CS/PVA) composite membrane on the proton conduction properties for fuel cell applications. The CS/SPVA membranes were prepared with different CS to PVA ratios with a fixed mass of crosslinker. The result...

This work reports utilised of RGO from Sengon wood biomass to support Fe–N–C noble-free catalyst (Fe–N-RGO), while also attempt to investigate the effect of pyrolysis stage on Fe–N-RGO catalysts with four different nitrogen precursors towards the ORR activity in acidic medium. One- and two-step pyrolysis were performed at 900 °C for 1 h and 2 h res...

A commercial perfluorinated sulfonic acid (PFSA) membrane, Nafion, shows outstanding conductivity under conditions of a fully humidified surrounding. Nevertheless, the use of Nafion membranes that operate only at low temperature (<100 °C) can lead to some disadvantages in PEMFC systems, such as a low impurity tolerance and slow kinetics. To overcom...

Non-precious metals (NPM) such as iron and nitrogen-doped carbon (Fe-N-C) have been actively studied as alternative electrocatalysts to platinum for oxygen reduction reaction (ORR) in proton exchange membrane fuel cell (PEMFC). However, its low stability is associated to the structural morphology of the electrode made of Fe-N-C and its support that...

Perfluorosulphonic acid-based membranes such as Nafion are widely used in fuel cell applications. However, these membranes have several drawbacks, including high expense, non-eco-friendliness, and low proton conductivity under anhydrous conditions. Biopolymer-based membranes, such as chitosan (CS), cellulose, and carrageenan, are popular. They have...

In this study, polypyrrole/toluene sulfonic acid-based nitrogen doped carbon nanotube (NCNT) is synthesized via chemical oxidative polymerization followed by high-temperature heat treatment under N2 atmosphere. The structure, morphology and composition of the NCNT catalyst are investigated with X-ray diffraction (XRD), scanning electron microscopy...

Reduced graphene oxide (RGO) has progressed as one of key emerging carbon for catalyst support material. As an alternative to the conventional RGO precursor, bio- mass Sengon wood was converted into RGO for use as a noble metal free catalyst support in oxygen reduction reaction (ORR). This work intends to reveal the applica- bility of Sengon wood-d...

Highly active nitrogen-doped carbon xerogel (N-CX) electrocatalysts for the oxygen reduction reaction (ORR) were synthesized through a simple sol-gel method. The N-CX samples are prepared using resorcinol – formaldehyde resin as the carbon precursor and dicyandiamide as the nitrogen precursor. The N-CX samples carbonized at different temperatures a...

Poly(vinyl alcohol) (PVA) is a biodegradable, water-soluble membrane that has low methanol permeation and reactive chemical functionalities. Modification of these features makes PVA an attractive proton exchange membrane (PEM) alternative to NafionTM. However, the pristine PVA membrane is a poorer proton conductor than the NafionTM membrane due to...

Nano-composite polymer electrolyte (NCPE), poly(vinylidenefluoride-hexafluoropropylene)-poly(methylmethacrylate) grafted natural rubber with lithium tetrafluoroborate and zirconia (PVdF-HFP/MG49-LiBF4-ZrO2) was prepared by a facile one-pot in situ sol–gel method. The influence of zirconia nano-fillers on the electrochemical, chemical and structural...

Herein, we report a facile procedure to synthesize the hybrid magnetic catalyst (Ru@CS-CR@Mn) using ruthenium (Ru) supported on ionically cross-linked chitosan-carrageenan (CS-CR) and manganese ferrite (MnFe2O4) nanoparticles with excellent catalytic activity. The ionic gelation of CS-CR is acting as a protecting layer to promote the encapsulation...

For the past decade, much attention was focused on polysaccharide natural resources for various purposes. Throughout the works, several efforts were reported to prepare new function of chitosan by chemical modifications for renewable energy, such as fuel cell application. This paper focuses on synthesis of the chitosan derivative, namely, O-nitroch...

Polymer electrolyte membranes, also known as proton exchange membranes (PEMs), are a type of semipermeable membrane that exhibits the property of conducting ions while impeding the mixing of reactant materials across the membrane. Due to the large potential and substantial number of applications of these materials, the development of proton exchang...

Sluggish oxygen reduction reaction (ORR) in cathode electrode is the most common problem in Proton Exchange Membrane (PEM) fuel cell systems. In this study, the ORR behaviours of a half-cell in the cathodic part were investigated which had an impact on its catalyst activity. The electrode was synthesized from multi-walled carbon nanotubes (MWCNT) s...

Solid acid composites of CsH 2 PO 4 /NaH 2 PO 4 /SiO 2 (CDP/SDP/SiO 2 ) were synthesised with varied SDP to CDP and SiO 2 to CDP mole fractions. The composites were arranged for optimisation via the Taguchi method with L9 orthogonal array, which manipulates four factors: the amount of SDP, amount of SiO 2 , amount of pressure used for pellet produc...

This study aims to develop a small size of TNF using an electrospinning process. TNF is applied in direct methanol fuel cell (DMFC) as a catalyst, catalyst support and a filler in the membrane. This study involves determining the parameters that affect the electrospinning process, particularly in terms of the distance between the needle tip and col...

Aryl diazonium salts are coupling agents that assist in molecules attachment to interfaces for sensing purposes. Despite not being fully explored and not yet widely applicable for cell-based sensors, the high stability of aryl diazonium salt formed sensing system is highly favorable in biological applications. Carbon-based electrodes are the most c...

Chitosan/poly(vinyl alcohol) (PVA) blend composite was prepared through two strategies of chemical modification, namely pre- and post-sulfonation. The sulfonation was carried out by using 4-sulfopthalic acid (sPTA) as the sulfonating agent. The modified chitosan/PVA blend composite was prepared under a range of chitosan content (10:90, 25:75, 50:50...

The high methanol crossover and high cost of Nafion® membrane are the major challenges for direct methanol fuel cell application. With the aim of solving these problems, a non-Nafion polymer electrolyte membrane with low methanol permeability and high proton conductivity based on the sodium alginate (SA) polymer as the matrix and sulfonated graphen...

Biocathode application in Microbial Fuel Cell (MFC) is a promising alternative for sustainable energy production. This recognition is due to its low construction and operation costs as well as the utilization of microbial metabolism in assisting power generation. One of the most crucial factors contributes to the performance of a biocathode MFC is...

This study optimized the H 3 PO 4 acid doping level (ADL) of polybenzimidazole (PBI) polymer electrolyte membranes using Taguchi method and characterized their ionic conductivity, contour plot and performed statistical regression analysis. Electrochemical impedance spectroscopic (EIS) analysis revealed that PBI copolymer-1 exposed better ionic cond...

In this study, graphene oxide (GO) as nano sized filler to improve the properties of polymer electrolyte membrane was synthesized via the modified Hummers method. Hummers is the most common method used to synthesize GO. The GO is produced by exfoliation of graphite oxide under sonication method. Dispersion by sonication method shows mechanical disr...

This work aims to study the effect of choline chloride (ChCl) and urea based deep eutectic solvent (DES) on the proton conduction and thermal properties of chitosan-carboxymethylcellulose (Chitosan-CMC) membrane. Chitosan-CMC biocomposites were prepared in different ratios of 5:95, 10:90, 25:75, 50:50 and 75:25 with DES and was characterised. This...

The potential for using O-methylene phosphonic κ-carrageenan (OMPk) as a filler in the chitosan-based polymer electrolyte N-methylene phosphonic chitosan (NMPC) was investigated. OMPk, a derivative of κ-carrageenan, was synthesized via phosphorylation and characterized using infrared spectroscopy (IR) and nuclear magnetic resonance (NMR). Both the...

Hydrogen is considered a fuel of the future due to its diversified supply and zero greenhouse gas emission. The application of advanced membrane technology for hydrogen separation within the larger hydrogen production process context can substitute the use of more expensive and energy intensive cryogenic distillation and pressure swing adsorption t...

Pulse current electrodeposition (PCE) technique was used to prepare graphene-supported platinum nanoparticles (GN-PtNPs) electrodes for the methanol electro-oxidation reaction in acidic media. The influences of the PCE parameters (applied current density, concentration of the Pt precursor, and duty cycle) upon the as-prepared GN-PtNPs electrodes fo...

Direct methanol fuel cell (DMFC) is a promising power source technology, but it has been unable to be successfully commercialized due to its high cost and low kinetic oxidation. Both problems stem from one of its main components, the catalyst. Therefore, this study is focused on determining and optimizing the electrocatalyst parameters of a high-pe...

In this work, a comprehensive study on the polyol synthesis of platinum supported on reduced graphene oxide (Pt/rGO) catalysts, including both ex-situ and in-situ characterizations of the prepared Pt/rGO catalysts, was performed. The polyol synthesis was studied considering the influence of the platinum precursor, oxidation level of graphite oxide...

In this study, cobalt-doped carbon xerogel (Co-CX) was synthesised via sol-gel polymerisation of phenolic compounds (i.e., resorcinol, phenol and m-cresol) and formaldehyde, and this polymerisation was catalysed by cobalt nitrate and followed by a carbonisation process. The effect of the initial pH value (5.5, 6.5 and 7.5) as well as the type of ca...

This study introduces a novel titanium dioxide carbon nanofiber (TiO2-CNF) support for anodic catalyst in direct methanol fuel cell. The catalytic synthesis process involves several methods, namely the sol-gel, electrospinning, and deposition methods. The synthesized electrocatalyst is compared with other three electrocatalysts with different types...

Carbon and other platinum-supporting materials have been studied as electrode catalyst component of low-temperature fuel cells. Platinum (Pt) is commonly used as the catalyst due to its high electro-catalytic activity. Current research is now focusing on using either modified carbon-based or non-carbon-based materials as catalyst supports to enhanc...

In its application, metal is always in contact with its environment whether air, vapor, water, and other chemicals. During contact, chemical interactions emerge between metals and their respective environments such that the metal surface corrodes. This study aims to determine the corrosion rate of 316L stainless steel sulphuric acid environment (H2...

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An enzyme-based electrochemical biosensor was investigated for the analysis of Sunset Yellow synthetic food dye. A glassy carbon electrode was coated with a poly(acrylamide-co-ethyl methacrylate) membrane to immobilize laccase using a single-step photopolymerization procedure. Poly(acrylamide-co-ethyl methacrylate) membrane was demonstrated to have...

Hydrogen share in the energy market has increased significantly in line with greater demand for zero emission fuel and the development of novel production routes via renewable resources. The application of mixed protonic–electronic conducting (MPEC) ceramic membrane within the hydrogen production process is an innovative route that enables high pur...

In this study, cobalt-doped carbon xerogel (Co-CX) was synthesized via sol-gel polymerization resorcinol-formaldehyde, catalyzed with cobalt nitrate, followed by drying and carbonization process under nitrogen gas flow. The effect of initial pH value (5.5, 6.5 and 7.5) and the type of carbon precursors on the morphology of Co-CX have been investiga...

Platinum (Pt) is the common catalyst used in a direct methanol fuel cell (DMFC). However, Pt can lead towards catalyst poisoning by carbonaceous species, thus reduces the performance of DMFC. Thus, this study focuses on the fabrication of a new composite TiO2 carbon nanofiber anodic catalyst support for direct methanol fuel cells (DMFCs) via electr...

Plasticisers have been widely used as additives in polymer applications, including pharmaceuticals, food processing, and electrochemical sensing, to improve the mechanical and physicochemical properties of the polymers. Recent developments using alternatives to the conventional phthalate ester plasticisers, such as water, ionic liquids (ILs) and de...

Hydrogen share in the energy market has increased significantly in line with greater demand for zero emission fuel and the development of novel production routes via renewable resources. The application of mixed protonic-electronic conducting (MPEC) ceramic membrane within the hydrogen production process is an innovative route that enables high pur...

This study presents a novel anodic PdAu/VGCNF catalyst for electro-oxidation in a glycerol fuel cell. The reaction conditions are critical issues affecting the glycerol electro-oxidation performance. This study presents the effects of catalyst loading, temperature, and electrolyte concentration. The glycerol oxidation performance of the PdAu/VGCNF...

Polymer electrolyte membranes based on the natural polymer κ-carrageenan were modified and characterized for application in electrochemical devices. In general, pure κ-carrageenan membranes show a low ionic conductivity. New membranes were developed by chemically modifying κ-carrageenan via phosphorylation to produce O-methylene phosphonic κ-carrag...

Currently, platinum is used as the cathode catalyst in direct methanol fuel cells (DMFCs). However, platinum reduces the number of active sites for the oxygen reduction reaction (ORR) due to the reaction between platinum and methanol and the strong adsorption of carbon monoxide molecules on the platinum surface, and in addition, platinum is very ex...

In this study, Aurum (Au) was used as the second metal in palladium catalyst (Pd) and carbon nanofiber (CNF) as catalyst support for glycerol oxidation. Second metal and catalyst support will help to improve catalytic activity and decrease adsorbed oxidation intermediates species. Carbon nanofiber supported PdAu nanoparticles was synthesized by usi...