Unveiling Atomic‐Scale Product Selectivity at the Cocatalyst‐TiO₂ Interface Using X‐Ray Techniques: Insights into Interface Reactivity

Abstract The microstructure at the interface between the cocatalyst and semiconductor plays a vital role in concentrating photo‐induced carriers and reactants. However, observing the atomic arrangement of this interface directly using an electron microscope is challenging due to the coverings of the semiconductor and cocatalyst. To address this, multiple metal‐semiconductor interfaces on three TiO₂ crystal facets (M/TiO₂─N, where M represents Ag, Au, and Pt, and N represents the 001, 010, and 101 single crystal facets). The identical surface atomic configuration of the TiO2 facets allowed us to investigate the evolution of the microstructure within these constructs using spectroscopies and DFT calculations. For the first time, they observed the transformation of saturated Ti_6c─O bonds into unsaturated Ti_5c─O and Ti_6c─O─Pt bonds on the TiO₂─010 facet after loading Pt. This transformation have a direct impact on the selectivity of the resulting products, leading to the generation of CO and CH₄ at the Ti_6c─O─Pt and Pt sites, respectively. These findings pinpoint the pivotal roles played by the atomic arrangement at the M/TiO₂─N interfaces and provide valuable insights for the development of new methodologies using conventional lab‐grade equipment.