G. Sasikumar

Bio: G. Sasikumar is an academic researcher from Sri Venkateswara College of Engineering. The author has contributed to research in topics: Proton exchange membrane fuel cell & Hydrogen production. The author has an hindex of 5, co-authored 6 publications receiving 117 citations.

Methanol Electrolysis for Hydrogen Production Using Polymer Electrolyte Membrane: A Mini-Review

Abstract: Hydrogen (H2) has attained significant benefits as an energy carrier due to its gross calorific value (GCV) and inherently clean operation. Thus, hydrogen as a fuel can lead to global sustainability. Conventional H2 production is predominantly through fossil fuels, and electrolysis is now identified to be most promising for H2 generation. This review describes the recent state of the art and challenges on ultra-pure H2 production through methanol electrolysis that incorporate polymer electrolyte membrane (PEM). It also discusses about the methanol electrochemical reforming catalysts as well as the impact of this process via PEM. The efficiency of H2 production depends on the different components of the PEM fuel cells, which are bipolar plates, current collector, and membrane electrode assembly. The efficiency also changes with the nature and type of the fuel, fuel/oxygen ratio, pressure, temperature, humidity, cell potential, and interfacial electronic level interaction between the redox levels of electrolyte and band gap edges of the semiconductor membranes. Diverse operating conditions such as concentration of methanol, cell temperature, catalyst loading, membrane thickness, and cell voltage that affect the performance are critically addressed. Comparison of various methanol electrolyzer systems are performed to validate the significance of methanol economy to match the future sustainable energy demands.

Effect of nitrogen and carbon dioxide as fuel impurities on PEM fuel cell performances

Abstract: Polymer electrolyte membrane (PEM) fuel cells are considered to have the highest power density of all the fuel cells. They operate on hydrogen fuel, which is generally produced by reforming of hydrocarbons, and may contain large amounts of impurities such as carbon dioxide, nitrogen, and trace amounts of carbon monoxide. We studied the effect of dilution of hydrogen gas with carbon dioxide on PEM fuel cells by polarization studies. The polarization curves were different when hydrogen gas was diluted with same quantities of carbon dioxide and with nitrogen. It may be due to carbon monoxide formation by reverse shift reaction and poisoning of anode platinum catalyst. Use of Pt–Ru alloy catalyst was found to suppress the poisoning. The effects of hydrogen gas composition, temperature, current density, and anode catalyst on fuel cell performances were examined in this study.

Development of nano-catalyzed membrane for PEM fuel cell applications

Abstract: Nano-catalyzed membrane with different platinum (Pt) catalyst loadings (0.25 to 1 mg cm−2) was investigated for proton exchange membrane fuel cell applications, and the Pt loading on the Nafion membrane was prepared by non-equilibrium impregnation reduction method. The prepared catalyzed membranes were subjected to various characterisations, namely, X-ray diffraction, high-resolution scanning electron microscopy (HRSEM) with energy-dispersive X-ray, cyclic voltammetry, polarisation and electrochemical impedance spectroscopy. The polycrystalline fcc cubic structure and the particle size of Pt catalyst were estimated by X-ray diffraction analysis. The membrane with 0.4 mg cm−2 of Pt loading exhibits a favourable surface morphology which is confirmed by HRSEM image. Electrochemical investigations were clearly evident that the uniform distributions of Pt particles with fine pores on Nafion membrane facilitated the three-phase boundary which leads to a better cell performance. Electrochemical impedance spectroscopy demonstrated that the cell constructed using 0.4 mg cm−2 of platinum-loaded membrane has lower resistance than the other Pt loading.

Low and non-platinum electrocatalysts for PEMFCs: Current status, challenges and prospects

Abstract: Platinum-based nanomaterials are the most commonly adopted electrocatalysts for both anode and cathode reactions in polymer electrolyte membrane fuel cells (PEMFCs) fed with hydrogen or low molecular alcohols. However, the scarce world reserves of Pt and its high price increases the total cost of the system and thus limits the feasibility of PEMFCs. Based on this problem, for PEMFCs to have wide practical applications and become commercially viable, the challenging issue of the high catalyst cost resulting from the exclusive adoption of Pt or Pt-based catalysts should be addressed. One of the targets of the scientific community is to reduce the Pt loading in membrane electrode assemblies (MEAs) to ca. 150 μ g c m MEA − 2 , simultaneously maintaining high PEMFCs performances. The present paper aims at providing the state-of-the-art of low Pt and non-Pt electrocatalysts for: (a) H2-O2 PEMFCs, (b) Direct Methanol Fuel Cells (DMFCs) and (c) Direct Ethanol Fuel Cells (DEFCs). The detailed analysis of a big number of recent investigations has shown that the highest mass specific power density (MSPD) value obtained for H2-O2 PEMFCs has far exceeded the 2015 target ( 5 mW μ g Pt total - 1 ) set by the USA department of energy, while a several number of investigations reported values between 1 and 5 mW μgPt−1. However, the highest values measured under DMFCs and DEFCs working conditions are still relatively low and close to 0.15 and 0.05 mW μgPt−1 respectively. Moreover, the last years, promising results have been reported concerning the design, fabrication, characterization, and testing of novel non-Pt (Pt-free) anodes and cathodes for PEMFCs applications.

Direct oxidation alkaline fuel cells: from materials to systems

Abstract: Direct oxidation alkaline fuel cells (DOAFCs) possess particular advantages on the possibility of employing low cost non-noble metal catalysts. A wide range of fuels can be used due to superior reaction kinetics in alkaline media. The development of DOAFCs was hindered by the carbonation of electrolyte due to the presence of CO2. The application of the anion exchange membrane (AEM) provides the possibility of reducing the effect of carbonation and fuel crossover which is an issue in the proton exchange membrane fuel cells (PEMFCs). The latest developments in alkaline fuel cells are examined in this paper, considering different types of fuels, novel catalysts and anion exchange membranes. Moreover, alkaline fuel cell systems and configurations are studied, particularly the new designs for portable or microelectronic devices. Further development of DOAFCs will rely on novel AEMs with good ionic conductivity and stability, low cost non-Pt catalysts with high activity and good stability for various fuels and oxidant. We envisage that DOAFCs will play a major role in energy research and applications in the near future.