Charge transfer and spillover effect enabled high-performance titanium dioxide supported PtCu catalyst towards acidic oxygen reduction

Abstract

The development of active and durable low-Pt electrocatalysts for oxygen reduction reaction (ORR) is the key target for proton exchange membrane fuel cells. Herein, a charge transfer and spillover effect enabled efficient ordered porous titanium dioxide supported PtCu alloy-based carbon-free ORR catalyst (PtCu@TiO2-xN) is developed. Experimental characterization and theoretical analysis reveal that the rich oxygen vacancies and N-doping of TiO2 support promotes the electron transfer from PtCu to TiO2-xN, resulting in electron-deficient PtCu surface. This weakens the adsorption of ORR intermediates on PtCu, and simultaneously promotes their spillover from PtCu sites to adjacent TiO2-xN support. This dynamic renewal of the PtCu active sites allows the rapid proceed of ORR, and thus accelerating its reaction kinetics. Accordingly, the PtCu@TiO2-xN catalyst exhibits greatly enhanced ORR activity with a specific activity of 1.83 mA cm−2Pt, mass activity of 1.24 A mg−1Pt and excellent durability as well. The results show that the rational design of Pt-based catalyst with spillover effect is of great significance towards efficient ORR reaction.