Insight into the Synergistic Effect of the Oxide?Metal Interface on Hot Electron Excitation

초록

Understanding the role of electron transfer by energy dissipation during chemical reactions on metal catalyst surfaces is significant for elucidating the fundamental phenomena at solid?gas and solid-liquid interfaces [1]. Electronic excitation by molecular interactions between reactants and catalyst surfaces generates a flow of excited electrons with an energy of 1?3 eV; these are called hot electrons [2]. To reveal the chemically induced electronic excitations on metal catalyst surfaces, metal-semiconductor catalytic nanodiodes can be used for real-time hot electron detector [3]. In addition, recently, it was found that when the metal-oxide interface is formed, the excitation of hot electrons can be amplified [4].In this work, by employing our catalytic nanodiodes with well-defined oxide?metal interfaces [CeO2 nanocubes (NCs)/Pt/TiO2 Schottky nanodevices], which is the first platform for the quantitative analysis of electron transfer at interfacial sites, we observed electronic excitation under H2 oxidation at the CeO2/Pt interface in real time. Direct measurement of the electron transfer as a function of the concentration of interfacial sites (by controlling the coverages of deposited CeO2 on Pt) allowed us to investigate the effect of the oxide?metal interface on nonadiabatic electronic excitation during catalytic H2 oxidation. Surprisingly, we observed that the efficiency of hot electron excitation was the highest at a specific concentration of CeO2/Pt interfacial sites, confirming that the interface enhances hot electron excitation under exothermic catalytic reactions. Our operando techniques using Schottky nanodiodes with well-controlled oxide?metal interfaces enabled us to uncover the quantitative relationship between the nanoscale interface and hot electron excitation, thereby optimizing the catalytic performance, contributing to the rational design of future hot electron-based catalysts.