Graphene oxide /Polyaniline/ Pt-Co: Synthesis, characterization and catalytic activity towards ethanol electro oxidation

Lately, there is growing concern about minimizing the damage caused by the burning of fossil fuels, which represent most of the world energy matrix. Direct ethanol fuel cells (DEFCs), electrochemical devices which directly convert chemical energy to electricity via electro oxidation of ethanol as fuel, have become attractive due to their advantages including high efficiency, low operating temperature, and low/zero emission. But for commercialization of this technology, some barriers should be overcome. The slow reaction kinetics of ethanol oxidation has been widely noticed as one of the most important challenges which strongly depends on the used catalysts. Platinum (Pt) has been commonly implemented in DEFCs as catalyst layer on both anode and cathode side. To decrease amount of Pt loading and increase catalytic activity of Pt for ethanol oxidation, the Graphene oxide /Polyaniline was utilized as the support catalyst for platinum-cobalt (Pt-Co) alloy that was electrochemically deposited on its surface for ethanol oxidation reaction. . In this study, for the first time to our knowledge, we have systematically investigated the effects of graphene oxide (GO) and polyaniline (PANI) as a catalyst support on the electro catalytic activity of Pt–Co nanoparticles for ethanol oxidation used in fuel cell applications. Compositing properties of the resulting products were characterized by Fourier transform infrared spectroscopy (FT-IR). In terms of the electrochemical activity for ethanol oxidation examined by cyclic voltammetry (CV). Our nanocomposites at the atomic level makes the nanostructure highly durable and this modified electrode exhibited high electro catalytic activity towards ethanol oxidation. The specific peak current densities for ethanol oxidation reaction were 43 mA cm-2 for GO/PANI/Pt-Co. The onset potential for ethanol oxidation reaction on GO/PANI/Pt-Co catalysts occurred at ca. -0.54 V which indicates that GO/PANI/Pt-Co nanocomposites ameliorate kinetics of ethanol electro oxidation. The ratio of the forward anodic peak current to the backward anodic peak current indicates higher tolerance to intermediate carbon species, the ratios for GO/PANI/Pt-Co is calculated to be 0.93 which suggests that GO/PANI/Pt-Co has less carbonaceous accumulation and hence is much more tolerant toward CO poisoning. It can be concluded that utilizing of GO/PANI nanocomposites as support for Pt-Co electrocatlysts facilities the oxidation of ethanol suggesting that this catalyst can be recommended for application in DEFCs. These findings suggest promising applications for GO/PANI nanocomposites as catalyst supports, contingent upon the development of large scale Pt for employment of DEFCs in different backgrounds from small scale to large scale

کلیدواژه ها:

ethanol oxidation reaction ، direct ethanol fuel cells ، GO/PANI nanocomposites