Comparison of electrocatalytic activity of Pt1−xPdx/C catalysts for ethanol electro-oxidation in acidic and alkaline media

Abstract

In this paper, a comparision of Pt_1−xPd_x/C catalysts for ethanol-oxidation in acidic and alkaline media has been investigated. We prepared Pt_1−xPd_x/C catalysts with different ratios of Pt/Pd (x at% = 0, 27, 53, 77 and 100) by the formic acid reduction method. The obtained Pt_1−xPd_x/C catalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), induced coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Structural and morphological investigations of the as-prepared catalysts revealed that the metallic particle size increases with increasing Pd content in the catalyst. The electrocatalytic performances and stabilities of Pt_1−xPd_x/C catalysts were tested by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA) measurements for ethanol oxidation in acidic and alkaline media. The electrochemical measurements demonstrate that Pt_1−xPd_x/C catalysts exhibit much higher electrocatalytic activity for alcohol oxidation in alkaline media than that in acidic media. The composition of Pt/Pd has a significant impact on the ethanol-oxidation in both acidic and alkaline media. The Pt₂₃Pd₇₇/C catalyst shows the highest electrocatalytic performance with a mass specific peak current of 2453.7 mA mg_PtPd⁻¹ in alkaline media, which is higher than the Pt₇₇Pd₂₃/C with the maximum of peak current of 339.7 mA mg_PtPd⁻¹ in acidic media. Meanwhile, the effect of electrolyte, CH₃CH₂OH concentrations and scan rates was also studied for ethanol-oxidation in acidic and alkaline media.