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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 blending with different compositions and the addition of inorganic filler on the microstructure and physical properties of N-methylene phosphonic chitosan/poly (vinyl alcohol) (NMPC/PVA) composite membranes. In this work, the NMPC biopolymer and PVA polymer are used as host polymers to produce NMPC/PVA composite membranes with different compositions (30–70% NMPC content). Increasing NMPC content in the membranes increases their proton conductivity, and as NMPC/PVA-50 composite membrane demonstrates the highest conductivity (8.76 × 10−5 S cm−1 at room temperature), it is chosen to be the base membrane for modification by adding hygroscopic silicon dioxide (SiO2) filler into its membrane matrix. The loading of SiO2 filler is varied (0.5–10 wt.%) to study the influence of filler concentration on temperature-dependent proton conductivity of membranes. NMPC/PVA-SiO2 (4 wt.%) exhibits the highest proton conductivity of 5.08 × 10−4 S cm−1 at 100 °C. In conclusion, the study shows that chitosan can be modified to produce proton exchange membranes that demonstrate enhanced properties and performance with the addition of PVA and SiO2.
Nur Adiera Hanna Rosli; Kee Shyuan Loh; Wai Yin Wong; Tian Khoon Lee; Azizan Ahmad. Hybrid Composite Membrane of Phosphorylated Chitosan/Poly(Vinyl Alcohol)/Silica as a Proton Exchange Membrane. Membranes 2021, 11, 675 .
AMA StyleNur Adiera Hanna Rosli, Kee Shyuan Loh, Wai Yin Wong, Tian Khoon Lee, Azizan Ahmad. Hybrid Composite Membrane of Phosphorylated Chitosan/Poly(Vinyl Alcohol)/Silica as a Proton Exchange Membrane. Membranes. 2021; 11 (9):675.
Chicago/Turabian StyleNur Adiera Hanna Rosli; Kee Shyuan Loh; Wai Yin Wong; Tian Khoon Lee; Azizan Ahmad. 2021. "Hybrid Composite Membrane of Phosphorylated Chitosan/Poly(Vinyl Alcohol)/Silica as a Proton Exchange Membrane." Membranes 11, no. 9: 675.
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 functional groups in grafting, morphology, thermal stability, ion exchange capacity, water absorption, swelling and proton conductivity for the prepared membranes is discussed. Both hybrid membranes showed higher values in ion exchange capacity, water uptake and swelling rate as compared to the recast pure Nafion® membrane. The results also show that the proton conductivity of Nafion®/2–HEAF and Nafion®/PAN membranes increased with increasing ionic liquid concentrations. The maximum values of proton conductivity for Nafion®/2–HEAF and Nafion®/PAN membranes were 2.87 and 4.55 mScm−1, respectively, equivalent to 2.2 and 3.5 times that of the pure recast Nafion® membrane.
Jonathan Goh; Ainul Abdul Rahim; Mohd Masdar; Loh Shyuan. Enhanced Performance of Polymer Electrolyte Membranes via Modification with Ionic Liquids for Fuel Cell Applications. Membranes 2021, 11, 395 .
AMA StyleJonathan Goh, Ainul Abdul Rahim, Mohd Masdar, Loh Shyuan. Enhanced Performance of Polymer Electrolyte Membranes via Modification with Ionic Liquids for Fuel Cell Applications. Membranes. 2021; 11 (6):395.
Chicago/Turabian StyleJonathan Goh; Ainul Abdul Rahim; Mohd Masdar; Loh Shyuan. 2021. "Enhanced Performance of Polymer Electrolyte Membranes via Modification with Ionic Liquids for Fuel Cell Applications." Membranes 11, no. 6: 395.
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 improvement of its physicochemical properties, including ionic conductivity, ion exchange capacity, water uptake, swelling ratio, etc., and its thermo-mechano-chemical stability in high-pH and high-temperature conditions. Generally, the AEM radiation grafting processes are considered green synthesis because they are usually performed at room temperature and practically eliminated the use of catalysts and toxic solvents, yet the final products are homogeneous and high quality. The radiation grafting technique is capable of modifying the hydrophilic and hydrophobic domains to control the ionic properties of membrane as well as its water uptake and swelling ratio without scarifying its mechanical properties. Researchers also showed that the chemical stability of AEMs can be improved by grafting spacers onto base polymers. The effects of irradiation dose and dose rate on the performance of AEM were discussed. The long-term stability of membrane in alkaline solutions remains the main challenge to commercial use.
Kean Lim; Chun Wong; Wai Wong; Kee Loh; Sarala Selambakkannu; Nor Othman; Hsiharng Yang. Radiation-Grafted Anion-Exchange Membrane for Fuel Cell and Electrolyzer Applications: A Mini Review. Membranes 2021, 11, 397 .
AMA StyleKean Lim, Chun Wong, Wai Wong, Kee Loh, Sarala Selambakkannu, Nor Othman, Hsiharng Yang. Radiation-Grafted Anion-Exchange Membrane for Fuel Cell and Electrolyzer Applications: A Mini Review. Membranes. 2021; 11 (6):397.
Chicago/Turabian StyleKean Lim; Chun Wong; Wai Wong; Kee Loh; Sarala Selambakkannu; Nor Othman; Hsiharng Yang. 2021. "Radiation-Grafted Anion-Exchange Membrane for Fuel Cell and Electrolyzer Applications: A Mini Review." Membranes 11, no. 6: 397.
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 important properties with great accuracy. In this work, MD simulations of chitosan/sulfonated poly (vinyl) alcohol (CS/SPVA) composite membranes produced in our previous experimental work are performed. First, the miscibility of the CS/SPVA composite is confirmed by simulating the Flory-Huggins interaction χ, which satisfies the condition χ < χcritical. In terms of thermal stability, the glass transition temperature Tg of the CS/SPVA composite is simulated at a value of 430 K (with only 3.18% deviation from the literature data). This suggests that the composite membrane satisfied the fuel cell working condition of 353 K. The proton conductivity was quantified by the ability of hydronium ions to diffuse into the polymer matrix. The simulated data demonstrated a higher proton conductivity in the CS/SPVA15 composite membrane than in the single SPVA membrane, with a computed value of 11.15 mS/cm. In addition, the RDFs agree with the Grotthuss-type proton transfer mechanism proposed in the CS/SPVA15 polymer model. In addition, better mechanical properties are reported with CS/SPVA15 composite membranes, with an approximately 110% improvement in the average Young's modulus. This suggests that the composite membrane has a much more compact and rigid structure than the SPVA membrane. This is beneficial for achieving an electrolyte polymer with better dimensional stability, which could prevent potential membrane failure during fuel cell operation. It can be concluded that the CS/SPVA composite displays superior thermal and mechanical stability, as well as proton conductivity, compared to the SPVA membrane.
Chun Yik Wong; Wai Yin Wong; Lijun Liu; Yoji Shibutani; Kee Shyuan Loh. Molecular dynamic simulation approach to understand the physical and proton transport properties of chitosan/sulfonated Poly(Vinyl alcohol) composite membranes. Polymer 2021, 217, 123458 .
AMA StyleChun Yik Wong, Wai Yin Wong, Lijun Liu, Yoji Shibutani, Kee Shyuan Loh. Molecular dynamic simulation approach to understand the physical and proton transport properties of chitosan/sulfonated Poly(Vinyl alcohol) composite membranes. Polymer. 2021; 217 ():123458.
Chicago/Turabian StyleChun Yik Wong; Wai Yin Wong; Lijun Liu; Yoji Shibutani; Kee Shyuan Loh. 2021. "Molecular dynamic simulation approach to understand the physical and proton transport properties of chitosan/sulfonated Poly(Vinyl alcohol) composite membranes." Polymer 217, no. : 123458.
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 respectively to produce Fe–N-RGO. This work revealed that two-step pyrolysis was able to remove the volatile components and hence forming more graphitised, stable graphitic-N and Fe-Nx, synergistically improve the ORR activity with highest onset potential of 0.83 V vs RHE and limiting current density of 5.33 mA cm−2 reported on Fe-Pani-RGO 2py. An increase in the kinetic on Fe-Pani-RGO 2py with Tafel slope of 74 mV/dec operated at 80 °C was reported. The mesoporous structure on RGO increases the stability by 8% and better methanol tolerance when compared to a benchmark Pt/C catalyst.
Wulandhari Sudarsono; Wai Yin Wong; Kee Shyuan Loh; Edy Herianto Majlan; Nirwan Syarif; Kuan-Ying Kok; Rozan Mohamad Yunus; Kean Long Lim; Ikutaro Hamada. Sengon wood-derived RGO supported Fe-based electrocatalyst with stabilized graphitic N-bond for oxygen reduction reaction in acidic medium. International Journal of Hydrogen Energy 2020, 45, 23237 -23253.
AMA StyleWulandhari Sudarsono, Wai Yin Wong, Kee Shyuan Loh, Edy Herianto Majlan, Nirwan Syarif, Kuan-Ying Kok, Rozan Mohamad Yunus, Kean Long Lim, Ikutaro Hamada. Sengon wood-derived RGO supported Fe-based electrocatalyst with stabilized graphitic N-bond for oxygen reduction reaction in acidic medium. International Journal of Hydrogen Energy. 2020; 45 (43):23237-23253.
Chicago/Turabian StyleWulandhari Sudarsono; Wai Yin Wong; Kee Shyuan Loh; Edy Herianto Majlan; Nirwan Syarif; Kuan-Ying Kok; Rozan Mohamad Yunus; Kean Long Lim; Ikutaro Hamada. 2020. "Sengon wood-derived RGO supported Fe-based electrocatalyst with stabilized graphitic N-bond for oxygen reduction reaction in acidic medium." International Journal of Hydrogen Energy 45, no. 43: 23237-23253.
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 overcome the above problems, this study introduces a highly durable composite membrane with an inorganic filler for a high-temperature proton exchange membrane fuel cell (HT-PEMFC) applications under anhydrous conditions. In this work, polybenzimidazole (PBI) is used as a polymer electrolyte membrane with the addition of a sulfonated graphene oxide (SGO) inorganic filler. The amount of SGO filler was varied (0.5–6 wt.%) to study its influence on proton conductivity at elevated temperature, mechanical stability as well as phosphoric acid doping level. In particular, PBI-SGO composite membranes exhibited higher the level of acid dopant and proton conductivities than those of the pure PBI membranes. The PBI-SGO 2 wt.% composite membrane displayed the highest proton conductivity, with a value of 9.142 mS cm−1 at 25 °C, and it increased to 29.30 mS cm−1 at 150 °C. The PBI-SGO 2 wt.% also displayed the maximum values in the acid doping level (11.63 mol of PA/PBI repeat unit) and mechanical stability (48.86 MPa) analyses. In the HT-PEMFC test, compared with a pristine PBI membrane, the maximum power density was increased by 40% with the use of a PBI composite membrane with 2 wt.% SGO. These results show that the PBI-SGO membrane has a great potential to be applied as an alternative membrane in HT-PEMFC applications, offering the possibility of improving impurity tolerance and kinetic reactions.
Yusra Nadzirah Yusoff; Kee Shyuan Loh; Wai Yin Wong; Wan Ramli Wan Daud; Tian Khoon Lee. Sulfonated graphene oxide as an inorganic filler in promoting the properties of a polybenzimidazole membrane as a high temperature proton exchange membrane. International Journal of Hydrogen Energy 2020, 45, 27510 -27526.
AMA StyleYusra Nadzirah Yusoff, Kee Shyuan Loh, Wai Yin Wong, Wan Ramli Wan Daud, Tian Khoon Lee. Sulfonated graphene oxide as an inorganic filler in promoting the properties of a polybenzimidazole membrane as a high temperature proton exchange membrane. International Journal of Hydrogen Energy. 2020; 45 (51):27510-27526.
Chicago/Turabian StyleYusra Nadzirah Yusoff; Kee Shyuan Loh; Wai Yin Wong; Wan Ramli Wan Daud; Tian Khoon Lee. 2020. "Sulfonated graphene oxide as an inorganic filler in promoting the properties of a polybenzimidazole membrane as a high temperature proton exchange membrane." International Journal of Hydrogen Energy 45, no. 51: 27510-27526.
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 been introduced and are being studied as alternative materials for enhancing fuel cell performance, because they are environmentally friendly and economical. Modifications that will enhance the proton conductivity of biopolymer-based membranes have been performed. Ionic liquids, which are good electrolytes, are studied for their potential to improve the ionic conductivity and thermal stability of fuel cell applications. This review summarizes the development and evolution of CS biopolymer-based membranes and ionic liquids in fuel cell applications over the past decade. It also focuses on the improved performances of fuel cell applications using biopolymer-based membranes and ionic liquids as promising clean energy.
Nur Adiera Hanna Rosli; Kee Shyuan Loh; Wai Yin Wong; Rozan Mohamad Yunus; Tian Khoon Lee; Azizan Ahmad; Seng Tong Chong. Review of Chitosan-Based Polymers as Proton Exchange Membranes and Roles of Chitosan-Supported Ionic Liquids. International Journal of Molecular Sciences 2020, 21, 632 .
AMA StyleNur Adiera Hanna Rosli, Kee Shyuan Loh, Wai Yin Wong, Rozan Mohamad Yunus, Tian Khoon Lee, Azizan Ahmad, Seng Tong Chong. Review of Chitosan-Based Polymers as Proton Exchange Membranes and Roles of Chitosan-Supported Ionic Liquids. International Journal of Molecular Sciences. 2020; 21 (2):632.
Chicago/Turabian StyleNur Adiera Hanna Rosli; Kee Shyuan Loh; Wai Yin Wong; Rozan Mohamad Yunus; Tian Khoon Lee; Azizan Ahmad; Seng Tong Chong. 2020. "Review of Chitosan-Based Polymers as Proton Exchange Membranes and Roles of Chitosan-Supported Ionic Liquids." International Journal of Molecular Sciences 21, no. 2: 632.
Azim Fitri Zainul Abidin; Kee Shyuan Loh; Wai Yin Wong; Abu Bakar Mohamad. Nitrogen-doped carbon xerogels catalyst for oxygen reduction reaction: Improved structural and catalytic activity by enhancing nitrogen species and cobalt insertion. International Journal of Hydrogen Energy 2019, 44, 28789 -28802.
AMA StyleAzim Fitri Zainul Abidin, Kee Shyuan Loh, Wai Yin Wong, Abu Bakar Mohamad. Nitrogen-doped carbon xerogels catalyst for oxygen reduction reaction: Improved structural and catalytic activity by enhancing nitrogen species and cobalt insertion. International Journal of Hydrogen Energy. 2019; 44 (54):28789-28802.
Chicago/Turabian StyleAzim Fitri Zainul Abidin; Kee Shyuan Loh; Wai Yin Wong; Abu Bakar Mohamad. 2019. "Nitrogen-doped carbon xerogels catalyst for oxygen reduction reaction: Improved structural and catalytic activity by enhancing nitrogen species and cobalt insertion." International Journal of Hydrogen Energy 44, no. 54: 28789-28802.
A bimetallic catalyst improves the physical and chemical properties of a bimetal because of an increased synergistic effect of the two different metals compared with those of their corresponding single particles. Therefore, in this study, a bimetal consisting of iron and cobalt (FeCo) supported with nitrogen-doped reduced graphene oxide (FeCo/NG) was successfully synthesised as a potential catalyst using a thermal annealing method for the oxygen reduction reaction (ORR). Dicyandiamide was used as the N precursor. Thermal annealing was performed at a high temperature (600 °C–800 °C) using transition metal precursors of FeCl3 and Co(NO3)2.6H2O with different Fe/Co molar ratios. The morphology analysis by means of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed that the average size of the FeCo nanoparticles is between 20 nm and 130 nm. With increasing annealing temperature, the size of the nanoparticles drastically grew, and they were well dispersed on the NG surface. XPS analysis revealed that the pyridinic-N configuration had the highest percentage of 62.61% compared to that of the others. This configuration acted as the active site for the enhanced ORR in an alkaline medium. The catalyst with a 1:2 molar ratio synthesised at 700 °C (1:2FeCo/NG700) exhibited the highest performance in 0.1 M KOH medium with a comparable potential of 0.74 V vs. RHE compared to those of the other catalysts. It exhibited a higher current density of 0.605 mA cm−2 compared with that of commercial Pt/C (0.75 V vs. RHE, 0.569 mA cm−2). Based on linear sweep voltammetry (LSV) analysis, the average number of electron transfers (n) of 1:2FeCo/NG700 was between 3.60 and 3.99 in the potential range of 0.0–1.0 V vs. RHE; this revealed that the 1:2FeCo/NG700 catalyst undergoes 4-electron pathways. These findings show that FeCo/NG is an active catalyst towards ORR in an alkaline medium, thereby justifying its use as a non-precious bimetallic catalyst for PEMFC application.
Shuaiba Samad; Kee Shyuan Loh; Wai Yin Wong; Wulandhari Sudarsono; Tian Khoon Lee; Wan Ramli Wan Daud. Effect of various Fe/Co ratios and annealing temperatures on a Fe/Co catalyst supported with nitrogen-doped reduced graphene oxide towards the oxygen reduction reaction. Journal of Alloys and Compounds 2019, 816, 152573 .
AMA StyleShuaiba Samad, Kee Shyuan Loh, Wai Yin Wong, Wulandhari Sudarsono, Tian Khoon Lee, Wan Ramli Wan Daud. Effect of various Fe/Co ratios and annealing temperatures on a Fe/Co catalyst supported with nitrogen-doped reduced graphene oxide towards the oxygen reduction reaction. Journal of Alloys and Compounds. 2019; 816 ():152573.
Chicago/Turabian StyleShuaiba Samad; Kee Shyuan Loh; Wai Yin Wong; Wulandhari Sudarsono; Tian Khoon Lee; Wan Ramli Wan Daud. 2019. "Effect of various Fe/Co ratios and annealing temperatures on a Fe/Co catalyst supported with nitrogen-doped reduced graphene oxide towards the oxygen reduction reaction." Journal of Alloys and Compounds 816, no. : 152573.
Herein, we report a facile procedure to synthesize the hybrid magnetic catalyst ([email protected]@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 of MnFe2O4 and Ru nanoparticles by electrostatic interactions. The presence of an active metal and a CS-CR layer on the as-prepared [email protected]@Mn catalyst was well determined by a series of physicochemical analyses. Subsequently, the catalytic performances of the [email protected]@Mn catalysts were further examined in the 4-nitrophenol (4-NP) reduction reaction in the presence of sodium borohydride (reducing agent) at ambient temperature. The [email protected]@Mn catalyst performed excellent catalytic activity in the 4-NP reduction, with a turnover frequency (TOF) values of 925 h−1 and rate constant (k) of 0.078 s−1. It is worth to mentioning that the [email protected]@Mn catalyst can be recycled and reused up to at least ten consecutive cycles in the 4-NP reduction with consistency in catalytic performance. The [email protected]@Mn catalyst is particularly attractive as a catalyst due to its superior catalytic activity and superparamagnetic properties for easy separation. We foresee this catalyst having high potential to be extended in a wide range of chemistry applications.
Kin Hong Liew; Tian Khoon Lee; Mohd Ambar Yarmo; Kee Shyuan Loh; Andreia F. Peixoto; Cristina Freire; Rahimi M. Yusop. Ruthenium Supported on Ionically Cross-linked Chitosan-Carrageenan Hybrid MnFe2O4 Catalysts for 4-Nitrophenol Reduction. Catalysts 2019, 9, 254 .
AMA StyleKin Hong Liew, Tian Khoon Lee, Mohd Ambar Yarmo, Kee Shyuan Loh, Andreia F. Peixoto, Cristina Freire, Rahimi M. Yusop. Ruthenium Supported on Ionically Cross-linked Chitosan-Carrageenan Hybrid MnFe2O4 Catalysts for 4-Nitrophenol Reduction. Catalysts. 2019; 9 (3):254.
Chicago/Turabian StyleKin Hong Liew; Tian Khoon Lee; Mohd Ambar Yarmo; Kee Shyuan Loh; Andreia F. Peixoto; Cristina Freire; Rahimi M. Yusop. 2019. "Ruthenium Supported on Ionically Cross-linked Chitosan-Carrageenan Hybrid MnFe2O4 Catalysts for 4-Nitrophenol Reduction." Catalysts 9, no. 3: 254.
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, 75:25 and 90:10). Water uptake and ion exchange capacity (IEC) of modified membranes were evaluated by titration and gravimetry methods respectively. Accordingly, both pre- and post-sulfonated composite showed a decrease in water uptakes and IEC values with an increase in chitosan content from 10 to 50 vol.%, attributed to the greater number of hydrogen bond pairs between the two polymers. At 75 vol.%, the composite was predicted to be dominant by the hydrophilic nature of chitosan, in which IEC values and water uptakes were shown to increase. The composite with 90 wt.% chitosan was found to be excessively hydrophilic with tremendously high water uptake, hence not suitable for fuel cell application. Besides that, the post-sulfonated composite showed a trend of increase in the IEC values and water uptakes with a decrease in chitosan content from 10 to 50 vol.%, and bounced back at 75 vol.%. Despite both pre- and post-sulfonation methods demonstrated similar trends in the results, it was notable that post-sulfonation method emerged with higher water uptake and ionic conductivity was found more favorable, attributed to the possibility that sulfonation took place on both PVA and chitosan which has caused a significant increase in sulfonic groups that purportedly exhibited higher ion transport mobility.
Chun Yik Wong; Wai Yin Wong; Kee Shyuan Loh; Wan Ramli Wan Daud; Kean Long Lim; Rashmi Walvekar; Mohamad Khalid. Comparative Study On Water Uptake And Ionic Transport Properties Of Pre- And Post Sulfonated Chitosan/PVA polymer Exchange Membrane. IOP Conference Series: Materials Science and Engineering 2018, 458, 012017 .
AMA StyleChun Yik Wong, Wai Yin Wong, Kee Shyuan Loh, Wan Ramli Wan Daud, Kean Long Lim, Rashmi Walvekar, Mohamad Khalid. Comparative Study On Water Uptake And Ionic Transport Properties Of Pre- And Post Sulfonated Chitosan/PVA polymer Exchange Membrane. IOP Conference Series: Materials Science and Engineering. 2018; 458 (1):012017.
Chicago/Turabian StyleChun Yik Wong; Wai Yin Wong; Kee Shyuan Loh; Wan Ramli Wan Daud; Kean Long Lim; Rashmi Walvekar; Mohamad Khalid. 2018. "Comparative Study On Water Uptake And Ionic Transport Properties Of Pre- And Post Sulfonated Chitosan/PVA polymer Exchange Membrane." IOP Conference Series: Materials Science and Engineering 458, no. 1: 012017.
Shuhib Mamat; Mohamad Faizzi; Mohd Sukor Su’Ait; Norasikin Ahmad Ludin; Kamaruzzaman Sopian; Nurul Akmaliah Dzulkurnain; Azizan Ahmad; Kee Shyuan Loh; Tian Khoon Lee; Daniel Brandell. Kajian Elektrolit Polimer berasaskan Getah Asli Terubah Suai (MG49) dalam Sel Suria Terpeka Pewarna. Sains Malaysiana 2018, 47, 2667 -2676.
AMA StyleShuhib Mamat, Mohamad Faizzi, Mohd Sukor Su’Ait, Norasikin Ahmad Ludin, Kamaruzzaman Sopian, Nurul Akmaliah Dzulkurnain, Azizan Ahmad, Kee Shyuan Loh, Tian Khoon Lee, Daniel Brandell. Kajian Elektrolit Polimer berasaskan Getah Asli Terubah Suai (MG49) dalam Sel Suria Terpeka Pewarna. Sains Malaysiana. 2018; 47 (11):2667-2676.
Chicago/Turabian StyleShuhib Mamat; Mohamad Faizzi; Mohd Sukor Su’Ait; Norasikin Ahmad Ludin; Kamaruzzaman Sopian; Nurul Akmaliah Dzulkurnain; Azizan Ahmad; Kee Shyuan Loh; Tian Khoon Lee; Daniel Brandell. 2018. "Kajian Elektrolit Polimer berasaskan Getah Asli Terubah Suai (MG49) dalam Sel Suria Terpeka Pewarna." Sains Malaysiana 47, no. 11: 2667-2676.
Kee Shyuan Loh; Universiti Kebangsaan Malaysia; Shuaiba Samad; Yusra Nadzirah Yusoff; Wai Yin Wong. Morphological Studies on the Agglomeration of FeCo Supported Nitrogen-doped Reduced Graphene Oxide Catalyst Prepared at Varying Annealing Temperature. Jurnal Kejuruteraan 2018, SI1, 31 -36.
AMA StyleKee Shyuan Loh, Universiti Kebangsaan Malaysia, Shuaiba Samad, Yusra Nadzirah Yusoff, Wai Yin Wong. Morphological Studies on the Agglomeration of FeCo Supported Nitrogen-doped Reduced Graphene Oxide Catalyst Prepared at Varying Annealing Temperature. Jurnal Kejuruteraan. 2018; SI1 (1):31-36.
Chicago/Turabian StyleKee Shyuan Loh; Universiti Kebangsaan Malaysia; Shuaiba Samad; Yusra Nadzirah Yusoff; Wai Yin Wong. 2018. "Morphological Studies on the Agglomeration of FeCo Supported Nitrogen-doped Reduced Graphene Oxide Catalyst Prepared at Varying Annealing Temperature." Jurnal Kejuruteraan SI1, no. 1: 31-36.
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 study showed a positive improvement the proton conductivity without excessive swelling using DES in comparison with those without DES, with a slight trade-off on the thermal stability. The sample corresponding to 50 wt% of chitosan showed the highest proton conductivity of 1.57 × 10−2 S/cm, which was slightly lower compared to Nafion-117 membrane (8.6 × 10−2 S/cm). The study revealed the blend film with 75 wt% of chitosan with the presence of DES has a potential for polymer electrolyte membrane (PEM) with a low but sufficient water uptake of 49.4% to avoid structural disintegration despite a lower proton conductivity obtained.
C.Y. Wong; W.Y. Wong; R. Walvekar; K.S. Loh; M. Khalid; K.L. Lim. Effect of deep eutectic solvent in proton conduction and thermal behaviour of chitosan-based membrane. Journal of Molecular Liquids 2018, 269, 675 -683.
AMA StyleC.Y. Wong, W.Y. Wong, R. Walvekar, K.S. Loh, M. Khalid, K.L. Lim. Effect of deep eutectic solvent in proton conduction and thermal behaviour of chitosan-based membrane. Journal of Molecular Liquids. 2018; 269 ():675-683.
Chicago/Turabian StyleC.Y. Wong; W.Y. Wong; R. Walvekar; K.S. Loh; M. Khalid; K.L. Lim. 2018. "Effect of deep eutectic solvent in proton conduction and thermal behaviour of chitosan-based membrane." Journal of Molecular Liquids 269, no. : 675-683.
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 for the methanol oxidation reaction (MOR) in terms of catalytic activity and tolerance against poisoning were studied using the Taguchi design of experiment (DOE). The analysis of variance (ANOVA) and signal-to-noise (S/N) ratio analysis provided prediction of optimal electrodeposition conditions to yield GN-PtNPs electrode which give the best MOR performance. The values of confirmatory experiment were demonstrated close to the values predicted using the Taguchi method. Transmission electron microscopy images showed that the Pt crystallites in flower-like structure were deposited evenly on the surface of graphene sheet. The Pt crystallites were predominantly in a zero-valent, metallic Pt state based on the X-ray photoelectron spectroscopy analysis.
S.Y. Toh; K.S. Loh; S.K. Kamarudin; W.R.W. Daud. Facile preparation of ultra-low Pt loading graphene-immobilized electrode for methanol oxidation reaction. International Journal of Hydrogen Energy 2018, 43, 16005 -16014.
AMA StyleS.Y. Toh, K.S. Loh, S.K. Kamarudin, W.R.W. Daud. Facile preparation of ultra-low Pt loading graphene-immobilized electrode for methanol oxidation reaction. International Journal of Hydrogen Energy. 2018; 43 (33):16005-16014.
Chicago/Turabian StyleS.Y. Toh; K.S. Loh; S.K. Kamarudin; W.R.W. Daud. 2018. "Facile preparation of ultra-low Pt loading graphene-immobilized electrode for methanol oxidation reaction." International Journal of Hydrogen Energy 43, no. 33: 16005-16014.
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 IR and NMR results confirmed the phosphorylation of the parent carrageenan. The solid polymer electrolyte (SPE)-based NMPC was prepared by solution casting with different weight percentages of OMPk ranging from 2 to 8 wt %. The tensile strength of the polymer membrane increased from 18.02 to 38.95 MPa as the amount of OMPk increased to 6 wt %. However, the increase in the ionic conductivity did not match the increase in the tensile strength. The highest ionic conductivity was achieved with 4 wt % OMPk, which resulted in 1.43 × 10−5 Scm−1. The κ-carrageenan-based OMPk filler strengthened the SPE while maintaining an acceptable level of ionic conductivity.
Joy Wei Yi Liew; Kee Shyuan Loh; Azizan Ahmad; Kean Long Lim; Wan Ramli Wan Daud. Effect of Modified Natural Filler O-Methylene Phosphonic κ-Carrageenan on Chitosan-Based Polymer Electrolytes. Energies 2018, 11, 1910 .
AMA StyleJoy Wei Yi Liew, Kee Shyuan Loh, Azizan Ahmad, Kean Long Lim, Wan Ramli Wan Daud. Effect of Modified Natural Filler O-Methylene Phosphonic κ-Carrageenan on Chitosan-Based Polymer Electrolytes. Energies. 2018; 11 (7):1910.
Chicago/Turabian StyleJoy Wei Yi Liew; Kee Shyuan Loh; Azizan Ahmad; Kean Long Lim; Wan Ramli Wan Daud. 2018. "Effect of Modified Natural Filler O-Methylene Phosphonic κ-Carrageenan on Chitosan-Based Polymer Electrolytes." Energies 11, no. 7: 1910.
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 technologies. This review overviews the basic aspects and progresses in perovskite-based proton conducting hydrogen separation membranes. Different configurations such as symmetric, asymmetric, hollow fiber, and surface modified perovskite membranes with various compositions are discussed and summarized. The challenges and future directions of such membranes are also elaborated.
Siti Salwa Hashim; Mahendra Rao Somalu; Kee Shyuan Loh; Shaomin Liu; Wei Zhou; Jaka Sunarso. Perovskite-based proton conducting membranes for hydrogen separation: A review. International Journal of Hydrogen Energy 2018, 43, 15281 -15305.
AMA StyleSiti Salwa Hashim, Mahendra Rao Somalu, Kee Shyuan Loh, Shaomin Liu, Wei Zhou, Jaka Sunarso. Perovskite-based proton conducting membranes for hydrogen separation: A review. International Journal of Hydrogen Energy. 2018; 43 (32):15281-15305.
Chicago/Turabian StyleSiti Salwa Hashim; Mahendra Rao Somalu; Kee Shyuan Loh; Shaomin Liu; Wei Zhou; Jaka Sunarso. 2018. "Perovskite-based proton conducting membranes for hydrogen separation: A review." International Journal of Hydrogen Energy 43, no. 32: 15281-15305.
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 carbon precursors on the structural properties of Co-CX was investigated via field emission scanning electron microscope (FESEM), Brunauer-Emmett-Teller (BET) and X-ray diffractometry (XRD). The catalytic activity of Co-CX for the oxygen reduction reaction (ORR) in 0.1 M KOH was studied using a rotating ring-disk electrode (RRDE) technique. The structural properties and ORR activities were affected by different initial pH values as well as the type of carbon precursor. A carbon precursor consisting of resorcinol-formaldehyde with an initial pH value of 7.5 exhibited the best catalytic activity. The initial pH plays an important role in promoting micro/mesopores. The FESEM and BET results revealed that Co doping promotes the formation of additional pores. The RRDE result indicated that Co-CX exhibited good catalytic activity that tends to favour a four-electron pathway.
Azim Fitri Zainul Abidin; Kee Shyuan Loh; Wai Yin Wong; Abu Bakar Mohamad; Ifa Puspasari. Effect of carbon precursor and initial pH on cobalt-doped carbon xerogel for oxygen reduction. International Journal of Hydrogen Energy 2018, 43, 11047 -11055.
AMA StyleAzim Fitri Zainul Abidin, Kee Shyuan Loh, Wai Yin Wong, Abu Bakar Mohamad, Ifa Puspasari. Effect of carbon precursor and initial pH on cobalt-doped carbon xerogel for oxygen reduction. International Journal of Hydrogen Energy. 2018; 43 (24):11047-11055.
Chicago/Turabian StyleAzim Fitri Zainul Abidin; Kee Shyuan Loh; Wai Yin Wong; Abu Bakar Mohamad; Ifa Puspasari. 2018. "Effect of carbon precursor and initial pH on cobalt-doped carbon xerogel for oxygen reduction." International Journal of Hydrogen Energy 43, no. 24: 11047-11055.
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 of support. All of these electrocatalysts differ based on a number of physical and electrochemical characteristics. Experimental results show that the TiO2-CNF support gave the highest current density at 345.64 mA mgcatalyst−1, which is equivalent to 5.54-fold that of carbon support while the power density is almost double that of the commercial electrocatalyst.
N. Abdullah; S. K. Kamarudin; L. K. Shyuan. Novel Anodic Catalyst Support for Direct Methanol Fuel Cell: Characterizations and Single-Cell Performances. Nanoscale Research Letters 2018, 13, 1 -13.
AMA StyleN. Abdullah, S. K. Kamarudin, L. K. Shyuan. Novel Anodic Catalyst Support for Direct Methanol Fuel Cell: Characterizations and Single-Cell Performances. Nanoscale Research Letters. 2018; 13 (1):1-13.
Chicago/Turabian StyleN. Abdullah; S. K. Kamarudin; L. K. Shyuan. 2018. "Novel Anodic Catalyst Support for Direct Methanol Fuel Cell: Characterizations and Single-Cell Performances." Nanoscale Research Letters 13, no. 1: 1-13.
Huina Wang; Xiaobin Wang; Bo Meng; Xiaoyao Tan; Kee Shyuan Loh; Jaka Sunarso; Shaomin Liu. Perovskite-based mixed protonic–electronic conducting membranes for hydrogen separation: Recent status and advances. Journal of Industrial and Engineering Chemistry 2018, 60, 297 -306.
AMA StyleHuina Wang, Xiaobin Wang, Bo Meng, Xiaoyao Tan, Kee Shyuan Loh, Jaka Sunarso, Shaomin Liu. Perovskite-based mixed protonic–electronic conducting membranes for hydrogen separation: Recent status and advances. Journal of Industrial and Engineering Chemistry. 2018; 60 ():297-306.
Chicago/Turabian StyleHuina Wang; Xiaobin Wang; Bo Meng; Xiaoyao Tan; Kee Shyuan Loh; Jaka Sunarso; Shaomin Liu. 2018. "Perovskite-based mixed protonic–electronic conducting membranes for hydrogen separation: Recent status and advances." Journal of Industrial and Engineering Chemistry 60, no. : 297-306.