Synthesis and study of the highly effective catalytic activity of the Pt-LaFeO3 nanoparticles supported on polyaniline-chitosan for methanol electro-oxidation

In this study, polyaniline (PA) accompanied by chitosan (CH) were used as effective and proper support for nanoparticles. LaFeO3 (LFO) nanoparticles were synthesized by sol-gel method and characterized by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) techniques. Pt-LFO/PA-CH nanocatalyst was prepared by chemical reduction of H2PtCl6 by NaBH4 on PA-CH support in the presence of LFO nanoparticles. The morphology and distribution of nanoparticles were determined by transmission electron microscopy (TEM) images. The catalytic activity of Pt-LFO/PA-CH nanocatalyst for methanol electro-oxidation was studied through cyclic voltammetry and electrochemical impedance spectroscopy. The effects of some experimental factors for methanol electro-oxidation, such as methanol concentration, scan rate and temperature were studied on the prepared catalyst. The activation energy of the anodic peak of methanol oxidation at Pt-LFO/PA-CH was also calculated and its value was obtained 14.17 kJ mol-1. The catalytic activity of Pt-LFO/PA-CH catalyst for methanol electro-oxidation was compared with Pt/PA-CH catalyst. The electrochemically active surface area of Pt-LFO/PA-CH catalyst (77.46 m2g-1Pt) was obtained more than Pt/PA-CH (54.69 m2g-1Pt). At methanol concentration of 1.76 M, the anodic peak current density of methanol oxidation at Pt-LFO/PA-CH (377.58 mA cm-2) was obtained more than Pt/PA-CH catalyst (203.67 mA cm-2). Higher electrochemically active surface area and current density of Pt-LFO/PA-CH for methanol oxidation indicating very improved catalytic activity of Pt-LFO/PA-CH for methanol electro-oxidation. Thus, the prepared catalyst can be utilized as effective catalyst for methanol electro-oxidation in direct methanol fuel cells.