Evaluation of different fuel cell catalyst nano particle loading on carbon nanotube as catalyst layer support using homemade half cell

Fuel cells are considered as a source of green energy of the past two decades. Polymer electrolyte membrane fuel cells are devices in which, hydrogen and oxygen electrochemically react and produced water, electricity and heat. Basic cell is formed of two cathode and anode electrodes, which separated by an electrolyte. Electrode is made of three-phase of catalyst, ionomer and substrate. During the electrochemical reaction, the electrons pass through substrateand protons pass through the ionomer. Therefore, catalyst particles should have a good electrical connection with the carbon substrate and are in close contact with the membrane. Also, fuel cell electrode in addition to the electrical conductivity should be porous enough to enter reactantgases and leave the produced water of oxygen reduction. Multi wall carbon nanotubes (MWCNTs) are used to increase the available surface area of platinum, as oxygen reduction reaction catalyst. Also, due to the nanotube pores, the access of reactant gases to the three-phase interface could be easier. In this work, a commercial gas diffusion layer and multi wall carbon nanotube is used as substrate to improve the efficiency of the catalyst (1). Catalyst layer ink preparation Deposition of Pt nanoparticles on MWCNTs was achieved by reducing the Pt salt,H2PtCl6.6H2O, precursor in an ethanol-water solution. In a typical experiment, the commercially CNTs were put in a 50 mL flask. An appropriate amount of the precursor was added to the flask. The reduction reactions were performed under reflux conditions. Then, the CNTs with Pt nanoparticles on them were separated from the ethanol solution in the centrifuge and washed with distilled water (2).

Keywords:

Platinum nano particles , polymer electrolyte membrane fuel cell , half-cell , multi wall carbon nanotube