Abstract:

Developing CO-tolerant electrocatalysts is of great importance for the practical use of proton exchange membrane fuel cells (PEMFCs) fed with reforming hydrogen. Transitional metal oxides are a class of promising components to (i) alleviate the CO adsorption on Pt and (ii) provide as a stabilized support for Pt nanoparticles. Herein, we for the first time adopted an electrostatic assembly strategy to deposit Pt nanoparticles highly dispersed and uniformly on the hexagonal tungsten oxides (hex-WO₃) modified by polyethleneimine (PEI). Specially, by controlling the surface charges of hex-WO₃ and Pt nanoparticles oppositely, the Pt nanoparticles are driven to deposit on hex-WO₃ surface via electrostatic-assembly. The Pt/PEI-hex-WO₃ composites possess excellent dispersion of Pt nanoparticles with average size of less than 3 nm even at Pt loadings as high as 40 wt.%. The Pt/PEI-hex-WO₃ catalysts display superior catalytic activity and electrochemical stability for the hydrogen electro-oxidation (HOR) in the presence of CO and good PEMFC performance compared to the conventional carbon-supported Pt catalyst, which may be attributed to the bifunctional mechanism and a strong metal-support interaction (SMSI).