In Situ Generated Ti 3+ -Mediated Photocatalytic Methanol Decomposition to Carbon Monoxide and Hydrogen on a Rutile TiO 2 (100) Surface.

Photocatalysis of methanol on the TiO 2 surface is a prototype of photocatalytic reactions. Here, we unveil a synergistic effect of photoexcited electrons and holes on converting methanol to CO and H 2 on a rutile TiO 2 (100) surface. Upon Hg light irradiation, photoexcited holes oxidize methoxy species at the 5-fold coordinated Ti 4+ sites sequentially to formaldehyde and formate intermediates, while photoexcited electrons reduce the associated Ti 4+ sites to Ti 3+ sites. The formate intermediates selectively decompose to CO and H 2 mediated by the Ti 3+ sites at elevated temperatures. These results greatly enrich methanol photochemistry on the TiO 2 surface and point to a surface structure engineering strategy of oxide photocatalysts for photocatalytic direct methanol decomposition to CO and H 2 .