Decoding the counterintuitive role of electron transfer in photothermal ammonia synthesis over Ru/CeO2 catalysts

Abstract

The electron transfer process across a metal–semiconductor interface critically governs the catalytic process by modulating the electronic structure of catalysts, while this process becomes markedly complex in photothermal catalysis. Under light, localized surface plasmon resonance generated hot electrons may transfer across the interface, altering the whole electronic structure of catalysts. On the other hand, the separation of electron–hole pairs is beneficial to prolong the charge carrier lifetime, promoting photochemical reactions. Therefore, the impacts of electron transfer for photothermal catalytic reactions should be shaped mutually by these two effects. To our best knowledge, prolonging the charge carrier lifetime was widely reported to be useful, while the influence of photo-induced electronic structure change remains elusive. Herein, we constructed well-defined Ru/ceria Schottky heterojunction model catalysts to prove how the photo-induced electronic structure change caused by electron transfer influences ammonia synthesis. We found that the intentionally inhibited electron transfer improves the formation of an optimized electronic structure under light, improving reactant activation and spillover, finally leading to improved catalytic performance. Our finding offers a new perspective for rationally designing efficient photothermal catalysts by strategically managing electron transfer dynamics.