The PtPdAg/C electrocatalyst with Pt-rich surfaces via electrochemical dealloying of Ag and Pd for ethanol oxidation. (10th May 2017) - Yang, Zhongzhao
Graphical abstract: Highlights: PtPd3 Ag5 /C-D with the PtPdAg alloy cores and Pt-rich surfaces are synthesized. Ag oxidation induces Pd dissolution, which can generate more oxygenated species. EOR activity on PtPd3 Ag5 /C-D is 4500 mA mg −1, 6.22 times higher than that on Pt/C. The activity enhancement is due to the synergistic effect between Pt sites and Pd. Abstract: In this work, the PtAg2 /C-D and PtPd3 Ag5 /C-D catalysts with Pt-rich surfaces were fabricated via chemical reduction following electrochemical dealloying. The as-prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron spectroscopy (TEM), atomic adsorption spectroscopy (AAS), X-ray electron spectroscopy (XPS) and electrochemical methods It is found that external Ag atoms are dealloyed by the cyclic voltammetry (CV) to expose more Pt active sites on the surface, which enhances the electrocatalytic performance greatly. The addition of Pd as another sacrificing element triggers higher activity due to the synergistic effect between Pd and Pt. The mass activity of as-prepared PtAg2 /C-D catalyst reaches 3.35 times as high as that of Pt/C. The PtPd3 Ag5 /C-D catalyst has the highest electrocatalytic activity of 4500 mA mg −1, which is 6.22 and 1.87 times as high as those of mono-component Pt/C and Pd/C, respectively. Their high electrocatalytic activity is attributed to electronic effects, oxygen-containing species from Pd oxides and higher utilization of Pt.