Enhancement of Oxidation of Dimethyl Ether Through Utilization of SnO2 for Immobilization of Pt Catalytic Nanoparticles

Abstract

Pt/C+SnO2 nanoparticles catalysts with SnO2 and Vulcan XC-72 carbon black as the mixed support were synthesized by facile and effective ethylene glycol reduction methods, the effect of SnO2 with different contents on the performance of Pt/C+SnO2 catalysts in dimethyl ether electrooxidation and stability were investigated. The catalysts were physically characterized by energy dispersive analysis of X-ray diffraction (XRD), X-ray (EDAX), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). The results showed that Pt nanoparticles had a small size distribution. Moreover, Pt nanoparticles and SnO2 units were dispersed uniformly on the surface of carbon support. The results of cyclic voltammetry(CV), chronoamperometry(CP), accelerated potential cycling tests (APCT) and electrochemical impedance spectra (EIS) exhibited that Pt/C+SnO2 catalysts have higher electrooxidation activity and stability than Pt/C catalyst. SnO2 can adsorb OHads species, the addition of SnO2 could be benefit to improve the adsorption of DME on Pt/C+SnO2 surface and reduce the Pt poisoning effect. When the SnO2 content in the catalyst attained as high as 20 wt.%, the catalyst shows the greatest activity and stability towards DME oxidation. The excess amount of SnO2 might give rise to the cover of the active sites of Pt surface, which obstructed the further dimethyl ether electrooxidation.