Catalytic enhancement for alcohol oxidation by electrodeposited Pt on TiO25CuxNi modified graphene oxide

Abstract

A study was conducted to investigate the performance of various catalysts, including electrodeposited platinum (Pt), metal oxides (e.g., TiO₂5CuxNi), and graphene oxide (GO), for the electro-oxidation of alcohols (e.g., methanol, ethanol, and n-propanol) in acidic media. The catalysts were synthesized as GO–TiO₂5CuxNi/Pt composites, where x represents the nickel (Ni) content in weight percent (wt%) relative to TiO₂, with values of 3, 5, and 15. These composites were characterized using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical performance was assessed through cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The prepared GO–TiO₂5CuxNi/Pt catalyst composites exhibited higher activity compared to the GO/Pt catalyst. The presence of a coexisting phase structure comprising metals (Ni, Cu, and Ti) in oxides and the GO support, along with electrodeposited Pt nanoparticles, facilitated efficient electron transport, which is advantageous for electrocatalytic performance. The prepared catalysts demonstrated high mass activity and low onset potential, and their kinetic characteristics revealed small Tafel slopes and low charge transfer resistance. Slight variations in the mechanistic performance for the oxidation of alcohols were observed, highlighting the influence of the alcohol molecular weight on catalytic reactivity. Among the catalysts studied, the GO–TiO₂5Cu15Ni/Pt composite with ternary metal oxides exhibited the highest activity for alcohol electro-oxidation, with the following order of current intensity: ethanol > methanol > n-propanol. In conclusion, the GO–TiO₂5Cu15Ni/Pt catalyst composite nanoparticles demonstrated superior catalytic performance among the catalysts evaluated, suggesting its potential for application in direct alcohol fuel cells.