Chemistry

Photochemistry

Physics

Atomic physics

Methanol

Proton

Photocatalysis

Electron transfer

Catalysis

Quantum mechanics

Organic chemistry

Physical chemistry

Adsorption

Excited state

Dissociation (chemistry)

Biochemistry

Journal of the American Chemical Society

CH3OH on a single-crystal rutile TiO2(110) surface is a widely studied model system for heterogeneous photocatalysis. Using spin-polarized density functional theory with a hybrid functional (HSE06), we study the photocatalytic oxidation of CH3OH adsorbed at a coordinately unsaturated Ti site as an excited-state process with triplet spin multiplicity. The oxidation to CH2O is stepwise and involves a CH3O intermediate. The first O-H dissociation step follows an excitonic interfacial proton-coupled electron transfer mechanism where the hole-electron (h-e) pair generated during the excitation is bound, and the h is transferred to the adsorbate. The O-H dissociation paths associated with other h-e pairs are unreactive, and the moderate experimental efficiency is due to the different reactivity of the h-e pairs. The excited-state CH3O intermediate further deactivates through a seam of intersection between the ground and excited states. It can follow three different paths, regeneration of adsorbed CH3OH or formation...

Excitonic Interfacial Proton-Coupled Electron Transfer Mechanism in the Photocatalytic Oxidation of Methanol to Formaldehyde on TiO<sub>2</sub>(110)