Polymer electrolyte fuel cell is an attractive type of fuel cell, which has proved to be an interesting area for further investigation. This is due to several advantages such as minimal risk of electrolyte leakage, short warm-up time (due to moderate operating temperature) and high power density. Over the last decades, a substantial progress has been made to improve the performance and durability of the cell while working on strategies to reduce its cost of fabrication. These objectives are achieved through the development of a natural biopolymer-based ion exchange membrane. Chitosan and cellulose have demonstrated an outstanding potential due to their excellent thermal and mechanical properties, good water retention ability, low reactants permeability, biodegradability and renewability. These characteristics are essential for a high-performance membrane. Therefore, several modifications for chitosan and cellulose were studied to further improve its properties and enhance its performance. Hence, this paper aims to comprehensively review the current development of membrane fabrication which utilizes green materials like chitosan and cellulose. Besides that, the influence of these materials toward improving the membrane properties and performance for ion exchange membrane fuel cell applications are also reviewed. We hope that this perspective will be able to provide useful interpretations for the development of the next generation of polymer electrolyte membrane in fuel cell applications.
The present study explores the opportunity to enhance the hydrogen production rate (HPR) at lower voltage in water electrolysis process by introducing conductive nanoparticles into electrolyte. The development of sustainable, cost-effective, reliable, clean, efficient, and renewable resources of energy systems is crucial for meeting the increasing energy demand. Among the various technologies developed to produce hydrogen, water electrolysis is the simplest, easy to operate, and ready to use in many industries, but it is still not cost-effective. Three different conductive nanomaterials: graphene nanoflakes, multi-wall carbon nanotubes (MWCNTs), and indium tin oxide, were incorporated into acidic electrolyte solutions of the water-splitting process. Experimental results reveal that among these nanomaterials, the incorporation of MWCNTs and graphene nanoflakes into electrolyte solutions considerably improved HPR. The highest HPR was observed at MWCNTs concentration of between 0.25 and 0.5 wt%. At 0.5 wt% MWCNTs and applied voltage of 4 V, about 170% improvement in the HPR was achieved when compared to base case (without nanoparticles into the electrolyte). An applied voltage of 10 V with the same MWCNTs concentration produced the maximum HPR of 2.7 ml/min. At the same concentration and voltage, the introduction of graphene into the electrolyte produced HPR of 2.5 ml/min. The effects of acid concentration and temperature on the HPR were also investigated. The HPR gradually increased with increasing acid concentrations in the dispersion due to the concentrations of ionic activators, which weakens the strength between oxygen and hydrogen bonds. Higher temperature also ameliorates the HPR because of the reduced bond strength. This approach of using nanomaterials in the electrolysis process could save up to 30% of energy input during this procedure.
The use of lignocellulosic biomass in the production of bioenergy is escalating with time due to the increase in energy demand and ecological pollution. The purpose of this study is to examine the opportunities of biofuel production from Pennisetum purpureum which is an invasive perennial grass in Brunei Darussalam. The proximate analysis of the study showed that the proportions of moisture content (MC), volatile matter (VM), fixed carbon (FC), and ash content (AC) were 5.93%, 69.44%, 16.81%, and 7.82%, respectively. Moreover, the ratios of carbon (C), hydrogen (H), nitrogen (N), sulfur (S), and oxygen (O) provided by the ultimate analysis were 43.23%, 5.80%, 1.17%, 0.11%, and 41.76%, respectively. The low moisture content and the higher heating value (18.55 MJ/kg) marked this grass as a potential source of biomass. Fourier transform infrared spectroscopy revealed the strong bonds between O–H, C–H, C–O, C=O, and C=C in the biomass. The thermogravimetric and their derivative results depicted that the highest weight losses occurred at a temperature of 334 °C with a degradation rate of 6.56 °C/min for pyrolysis condition and at a temperature of 312 °C with a degradation rate of 7.66 °C/min in combustion conditions.
A low-temperature (< 42 °C) Ar dielectric barrier discharge jet (DBDjet) is used to treat screen-printed reduced graphene oxide (rGO)–polyaniline (PANI)–chitosan (CS) nanocomposites used as the electrodes of gel-electrolyte supercapacitors. X-ray photoelectron spectroscopy results indicate decreased C–O bonding content, suggesting a reaction with some CS, as well as increased C–N and –COOH contents that could be responsible for the improved hydrophilicity and the resulting enhancement in the capacity of the supercapacitor. Galvanostatic charging discharging measurements indicate that Ar DBDjet treatment improves the capacitance by 166%; these results are confirmed by cyclic voltammetry. Our results demonstrate that without substantial heating, Ar DBDjet reactive plasma species alone can improve the hydrophilicity of rGO–PANI–CS nanocomposites on carbon cloth.
Perovskite solar cells with organometal halides of inorganic–organic hybrid materials have been under investigation in the area of energy-conversion research and development. Among the various perovskite solar cells, the carbon-based hole-transporter-free type is a better option because of its low materials and manufacturing costs, availability, high efficiency, and long-term stability. In this study, carbon black (CB) and multiwall carbon nanotube (MWCNT) paste layers were prepared and applied to fluorine-doped tin oxide (FTO) conductive surfaces of the hole-transporter-free CH3NH3PbI3 perovskite solar cells as counter electrodes using the spin coating process. Cell performance studies were conducted on the prepared samples using a solar simulator. The effects of the current density–voltage (J–V) characteristics and hysteresis of perovskite solar cells of both CB- and MWCNT-based layers were evaluated in detail. It was determined that MWCNT-based solar cells have better short-circuit densities and possess higher power conversion efficiencies compared to CB paste-based solar cells. In both cases, the efficiencies of the carbon-based perovskite solar cells were considerably enhanced, which might be useful to improve the overall perovskite solar cell efficiencies.