Generally, it is possible to reduce the size, cost, and parasitic loss of polymer electrolyte membrane fuel cell (PEMFC) system with an air-cooled system, open cathode and self-humidifying stack for portable fuel cell application. In order to ensure the that PEMFC stack applicable for portable fuel cell application, a mathematical model is useful tool for saving design cost, giving a better system design and operation. Therefore, this study is focused on developing a simplified zero-dimensional mathematical model for self-humidifying and open cathode 200W PEMFC stack for portable fuel cell generator application. The mathematical equations are modelled by using Matlab-Simulink tools in order to simulate the operation of the developed mode. This simulation is then compared to a commercially 200W Horizon PEMFC stack (H-200) for data validation purposes. The air inlet flow rate is chosen to test the sensitivity of the fuel cell stack model. The air inlet stoichiometry of 2, 5, 20, and 50 was varied to generate a different air inlet flow rate. Based on the simulation, air inlet stoichiometry above 15 is sufficient to produce a high output stack voltage. However, in a real operation of the H-200 fuel cell stack system needs air inlet stoichiometry at about 20 because a fan is used to supply air and also the cooling system. High anode and cathode relative humidity result in a high output stack voltage. However, it is better to increase the anode relative humidity than cathode relative humidity to get high output stack voltage.

Keywords:  Polymer Electrolyte Membrane Fuel Cell; Simulink; Stoichiometry; Relative Humidity

LiCo2-based materials are well-known, widely used as cathode materials in lithium ion batteries and currently are also used in low temperature proton conducting solid oxide fuel cells (H+-SOFCs) application. Dopants such as Zn are introduced in LiCo2-based materials to improve the properties and performance of the materials for H+-SOFC application. In this study, Zn-doped LiCo2, LiCo0.6Zn0.4O2 (LCZO) powder was synthesized via glycinenitrate combustion method followed by various characterizations. The precursor LCZO powder dried at 100 °C was subjected to thermogravimetric analysis (TGA). The phase formation and morphology of the calcined LCZO powder at 600 °C were examined by an X-ray diffractometer (XRD) and a tabletop scanning electron microscope (SEM), respectively. The TGA result revealed that the thermal decomposition of the intermediate compounds in the precursor LCZO powder was completed at 800 °C through three main phases of weight losses. A pure phase of LCZO was not completely produced after the calcination at 600 °C due to the presence of secondary phases as confirmed from the XRD analysis. The identified secondary phases that present are confirmed as ZnCo2O4 and ZnO as documented in JCPDS file no. 00-001-1149 and JCPDS file no. 01-079-0205 consecutively. The SEM images showed that the impure calcined LCZO powder possessed homogeneous and fine particles.

Keywords: Solid Oxide Fuel Cell; LiCo0.6Zn0.4O2 cathode; Glycine-nitrate combustion method; single phase

A new catalyst based on mesostructured silica nanoparticle (5wt%, 20wt%, and 30wt% Ni-MSN) were prepared by the wet impregnation method and used for electro-oxidation of methanol. While, MSN as a catalyst support was synthesized using co-condensation and sol-gel method. The synthesized MSN and Ni-MSN were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier Transform Infra-red (FTIR) techniques. Ni-MSN catalysts were successfully prepared by mixing with the conducting graphite in 1:1 ratio which called carbon paste electrode (CPE). Mixing with graphite, in this work, was particular necessary to increase the electrical conductivity of the Ni-MSN materials. For fuel cell applications, the electrochemical measurements for methanol oxidation were investigated using cyclic voltammetry (CV) and chronoamperometry (CA) in 1.0 M NaOH and 1.0 M CH3OH for modified electrode, Ni-MSNCPE. Among the three samples, 30wt% Ni-MSNCPE exhibits a high current density (~8 mA cm-2) and long-term chronoamperometry stability (3600 s) toward methanol oxidation in alkaline solution. This may attribute to the high dispersion of nickel and ordered mesoporous structure which can facilitate the diffusion of methanol and products. 30wt% Ni nanoparticles supported onto MSN catalyst demonstrate better electrocatalytic activity and stability than the 5wt% and 20wt% Ni-MSNCPE catalysts.

Keywords : Mesostructured Silica Nanoparticle, anode catalyst, methanol oxidation reaction, modified electrode

This study is a follow-up study of a previous study that examined the effect of temperature on the mechanical performance of the polymer carbon composite (CCP). In this study, the optimal formulation obtained from previous studies, was tried for use in polymer fuel cells of high temperature polymer electrolytes. The standard used is, the standard for bending strength specified by the US Department of Energy (DOE) Agency, which has determined the bending strength should be higher than 25 MPa. Preparation of CCP bipolar plates is done by internal mixing and then molded by compression stirring method. Bending strength and hardness test are carried out at 26 ° C to 200 ° C, for 80% CNT / NG mixture and 20% by weight of EP, with a resin / hardener ratio of 3: 1. This composition has successfully met the bending strength standards set by the DOE on testing performed at room temperature. However, the composite electrical conductivity is still less than the standard set by DOE, reaching only 50 S / cm. The results show that the composite plate of CNT / NG / EP mixed with a 5/75/20% by weight composition is not suitable for HT-PEMFC, because the filler and matrix composite interface failed to hold the bonds at temperature higher than the melting point of the EP. It is therefore recommended that this composite material be used only at low temperatures and is also not recommended for use as a fuel cell plate.

Keywords: Polymer composite; Bipolar plate; Fuel cell; Compression molding; Flexural strength; Hardness

One of the barriers to the large-scale commercialization of proton exchange membrane fuel cells (PEMFCs) is the high-priced of noble metals such as platinum (Pt). Therefore, in this paper, bimetallic electrocatalyst FeCo supported nitrogen-doped reduced graphene oxide (FeCo-NG) for oxygen reduction reaction (ORR) is proposed and has been successfully prepared through annealing of a mixture containing Fe, Co salts, dicyandiamide (DCDA) and graphene oxide (GO). The starting material GO appeared to be in multilayer sheets through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Due to the high annealing temperature and the absence of the surfactant, agglomeration of FeCo nanoparticles was observed from the morphology analysis. The macrostructure size of the metals particles was observed to be increased over temperature. As the temperature increases, the agglomeration gets more intense because of the increased of van der Waals cohesive forces between the nanoparticles. In addition, the weak electrostatic interaction between the metal cations with the nitrogen and the GO sheets could also be the cause of the agglomeration. The weak electrostatic interaction caused the nanoparticles (Fe and Co) not attracted onto the GO sheets thus inhibit the reduction of FeCo and GO to occur in situ simultaneously. It is believed that the agglomeration of the electrocatalyst FeCo-NG could results to poor electrocatalytic activity of PEMFC.

Keywords: Agglomeration; Iron cobalt; Catalyst; Surfactant; Proton exchange membrane fuel cell

Renewable sources of energy are becoming increasingly popular in recent years. The idea of using alternative energy that utilizes renewable sources is to slowly replace our dependence on fossil fuels. Conventional fossil fuels are not viable due to the fact that they are predominantly unsustainable over the long run. Furthermore, pollution will be reduced through the use of cleaner and more environmentally friendly renewable energy. Polymer electrolyte membrane fuel cell (PEMFC), which utilizes hydrogen as fuel, has a high potential as an alternative power generator. The unitized regenerative fuel cell (URFC) is a type of PEMFC that can perform both in charge mode (as a fuel cell) and discharge mode (as an electrolyzer). This review looks into the recent researches on the structure and different components of the URFC. In particular, emphasis is placed on bifunctional electrodes. Recent development in URFC research has produced a more stable bifunctional electrode with improved energy efficiency and overall stability and durability. Various works have been carried out to replace Pt as the electrocatalyst, including the use of graphene as a low cost non-metal graphene-based electrocatalyst. Electrocatalyst support also plays an important role in increasing conductivity while reducing the catalyst resistance to corrosion. The technological challenges and limitations of the URFC system are also discussed in this review.

Keywords: Regenerative Fuel Cell; Water Electrolysis; Gas Diffusion Layer; Bifunctional Electrode

Excessive of agro wastes and crude glycerol required efficient management in order to avoid environmental pollution. Varieties of elements content in agro wastes and crude glycerol highly potential to become feedstock for production of biogas. The objective of this study was to investigate the improvement of biogas production by anaerobic co-digestion of agro wastes with crude glycerol. Sugarcane bagasse, dried leaves, corn stover, cattle manure and crude glycerol were used in production of biogas using anaerobic co-digestion method conducted at room temperature, pH 6.8-7.2 for 30 days in 2L of bio-reactor. The contain of crude glycerol was determined by Gas Chromatography Mass Spectrometer (GC-MS) while the present of bio-methane was analysed by Gas Chromatography Thermal Conductively Detector (GC-TCD). Meanwhile the bio-ethanol formed was detected by High Performance Liquid Chromatography (HPLC). Mixture of cattle manure, sugarcane bagasse, and crude glycerol content of highest C/N ratio (22.42) while co-digestion of these samples produced 20L biogas g-1 VS added. Meanwhile about 33.07 % to 42.27 % COD removal obtained in Experiment 1 while 27.86 % to 45.52 % COD removal obtained in Experiment 2. Co-digestion of cattle manure and sugarcane bagasse with crude glycerol produced 3.2 L biogas g-1 VS added. About 0.28 mg/L of acetic acids detected at day 20 in Experiment 1 while 0.28 mg/L of acetic acids detected in day 15 in Experiment 2. Therefore, this study proof that the co-digestion of cattle manure, agricultural wastes and crude glycerol resulted in higher biogas yields.

Keywords: Biogas; Methane; Glycerol; Agro Waste; Co-Digestion

Stainless steel 316L (SS316L) has the potential to be used as a bipolar plate for proton exchange membrane fuel cells (PEMFCs). SS316L has good electrical conductivity and passivity, but if used in acidic environments (pH 3-6), passivity will changed and cause corrosion. In this study, green inhibitor with an electrophoresis desposition (EPD) technique was used to reduce the corrosion of SS316L plates. The results of the scanning electron microscope (SEM) analysis show that the SS316L surface is smoother and thicker, with a thickness of between 4.9 – 8.9 μm. Testing using linear polarization Tafel method in 0.5 M H2SO4 medium, found that the corrosion current value (Icorr) decreased with the presence of the coating i.e. from 18.484 μA / cm2 to 0.859 μA / cm2, SS316L corrosion rate without coating is 0.7172 mpy, whereas SS316L coated with arabic gam has a lower corrosion rate of 0.033 mpy. From this study, the finding of this study showed that arabic gum with EPD coating technique can provide corrosion protection against the surface of SS316L.Keywords: Corrosion; Bipolar plate; Stainless steel 316L (SS316L; Arabic gum; Electrophoresis disposition.

This paper reviews on the latest use and performance of several types of metals as electrodes within the development of bioelectrochemical systems (BES) including microbial fuel cells (MFC) and microbial electrolysis cells (MEC). The conventional carbon-based electrodes are typically used as an anode or cathode since the structure of the material is porous and are most suitable for the growth of electrochemically active bacteria (EAB). However, there are new developments that show the use of metal electrodes capable of producing higher current density and maximum power than carbon, due to the properties of metals such as high conductivity and mechanical strength, anti-corrosion as well as chemical structure stability. The surface modification strategy of metal promotes the EAB attachment and increases the biocompatibility or electron transfer between bacterial cell and electrode. Besides, cost-effective and easy to operate for the long-term is a contributing factor to the use of metal electrodes. To date, stainless steel becomes a common metal used in the development of BES.

Keywords: Bioelectrochemical system; Electrode; Metal; Stainless steel; Carbon.

In the present study, cuprous oxide nanowire fabricated using wet chemical oxidation method was proven to produce high photoactive film for photoelectrochemical (PEC) water splitting. A relatively high photocurrent density of -5mA cm-2 at 0.6V vs Ag/AgCl was generated. The PEC performance is the reflection of intrinsic light absorption capacity at visible region which correspond to 2.0eV, an ideal band gap for PEC water splitting. Comparison with calculated data based on density functional theory using CASTEP shows that the band gap and light absorption capacity obtained from experimental work exhibited a close match. Hence, this study suggested that the preparation of Cu2O thin film via wet chemical oxidation method obeyed the theoretical prediction. However, the Cu2O is limited with poor stability in PEC condition attributed to the insufficient potential of its valence band to oxidize water. Therefore, an effort was directed to address the feasibility of shifting the valence band by modeling a doped Cu2O with several dopants using DFT technique. The selected dopants were Ag, Co, Ni and Zn. Preliminary conclusion of this study indicated that doping could be used to tune the band gap of Cu2O due to ionic radii of the dopant affected the shifting of band gap. In this study, Co showed more significant improvement of Cu2O for photoelctrochemical water splitting process. However, to validate the simulation, further study should be carried out experimentally.

Keywords: Copper Oxide; Chemical oxidation; band structure; Photo electrochemical; Hydrogen production