The heat-promoted metal–support interaction of a PtCu/SiO2 carbon-free catalyst for the methanol oxidation and oxygen reduction reactions

Abstract

Pt shows excellent catalytic activity and acid stability towards the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR), but suffers from deactivation due to the weak interaction with the carbon support and the oxidation of carbon under operation. To solve the problem, herein, silica nanospheres were used to load PtCu nanoparticles as the carbon-free catalyst for the MOR and ORR. It is found that the heat treatment is crucial to regulate the metal–support interaction and enhance the catalytic performance. The PtCu/SiO₂ catalyst after heat treatment exhibits a specific activity (SA) nearly 7 times the value of Pt/C toward the MOR, and much better durability. The MOR mass activity of heat-treated PtCu/SiO₂ is over twice the value of the untreated one. The electron transfer promoted by heat treatment leads to an upshift of the d-band center of Pt, resulting in the increase of the absorption rate of methanol and the intermediates.