Visualizing Elementary Reactions of Methanol by Electrons and Holes on TiO2(110) Surface

Direct visualization and comparison of the elementary reactions induced by electrons and holes are of importance for finding a way to conduct chemical reactions and reaction sequences in a controllable manner. As a semiconductor, TiO2 provides a playground to perform the measurements, and moreover, the information can be useful for design of high-performance TiO2-based catalysts and photocatalysts. Here, we present our investigation on the elementary reactions of CH3OH on TiO2 surface through visualization of specific elementary steps by highly controllable electron and hole injection using scanning tunneling microscopy. The distinct sequential routes and their kinetics, namely, breaking C–O and O–H bonds by electrons and breaking O–H and C–H bonds by holes, respectively, have been experimentally identified and well elucidated by density functional theory calculations. Our nonlocal h-injection experimental and theoretical results suggest that the delocalized holes in the TiO2 substrate should be responsib...