Photoelectron Storage at the WO3/TiO2 Interface: Modeling in Ambient Conditions from First-Principles Calculations

Usingfirst-principles calculations, we showed that the monoclinicWO(3)(001) preferentially forms a reconstructed monolayeron the anatase TiO2(001) surface. We thoroughly examinedthe structure of the WO3/TiO2 surface underambient conditions, i.e., in equilibrium with gas-phase O-2/H2O or H-2/H2O under a range ofpressure and temperature or in aqueous solution under a range of pHand electrochemical potential. Based on the WO3/TiO2 surface structures at different potentials, we proposed theproton-coupled electron-transfer (PCET) reaction pathway during chargingand oxygen reduction reaction (ORR) pathways during discharging, whichaccount for its reversible electron storage ability. With electronicstructure analysis, we depicted the charge separation effect of WO3 on TiO2 and the electron storage effect of WO3.

Automated summary

Using first-principles calculations, we found that monoclinic WO(3)(001) preferentially forms a reconstructed monolayer on anatase TiO2(001) surface. We studied the surface structure of WO3/TiO2 under ambient conditions, including gas-phase O-2/H2O or H-2/H2O at different pressures and temperatures, as well as aqueous solution at different pH and electrochemical potentials. Based on the surface structures at different potentials, we proposed the proton-coupled electron-transfer (PCET) reaction pathway during charging and the oxygen reduction reaction (ORR) pathways during discharging, which explain its reversible electron storage ability. With electronic structure analysis, we demonstrated the charge separation effect of WO3 on TiO2 and the electron storage effect of WO3.