Strong metal–support interaction (SMSI) modulates d-orbital centers to promote oxygen reduction reaction

Abstract

Hydrogen peroxide (H₂O₂) production through oxygen reduction mediated by semiconductor photocatalysts is a typical reaction for converting solar energy to chemical energy, in which the adsorption and activation of oxygen on the catalyst is the rate-controlling process. To improve the catalytic performance of the catalyst, attention must be paid to the charge transfer effect on molecular orbitals. Hence, carbon–nitrogen support structures have been developed, and Ag clusters can be stably anchored on carbon–nitrogen supports due to the strong metal–support interaction (SMSI). The effect of SMSI and the difference in work function contribute to the antibonding orbitals of active oxygen-accepting Ag atom d-orbital electrons being activated. The experimental results show that the formation of H₂O₂ follows two-electron transfer processes for oxygen reduction. The photoactivity of the system is 6410.7 μmol g⁻¹ h⁻¹ and the photochemical conversion is 1.06%. These results provide a theoretical basis for further study of the effect of interfacial charge transfer on molecular orbitals.