Abstract
Oxidation and reduction steps in catalysis are always in series, and excellent activity can be achieved when they occur in close proximity. Photooxidation and photoreduction are generally separated and rarely in series. This work develops defect engineering at the metal–oxide interface to make photooxidation sites close to photoreduction sites. Taking solar hydrogen production from aqueous alcohols over Pt/
T
i
O
2
as an example, the proximity effect triggers unusual reactions and thus increases hydrogen yield per photon from 0.046 to 1.28. Our study provides a direction for the development of efficient photocatalysis.
Close proximity between different catalytic sites is crucial for accelerating or even enabling many important catalytic reactions. Photooxidation and photoreduction in photocatalysis are generally separated from each other, which arises from the hole–electron separation on photocatalyst surface. Here, we show with widely studied photocatalyst Pt/
T
i
O
2
as a model, that concentrating abundant oxygen vacancies only at the metal–oxide interface can locate hole-driven oxidation sites in proximity to electron-driven reduction sites for triggering unusual reactions. Solar hydrogen production from aqueous-phase alcohols, whose hydrogen yield per photon is theoretically limited below 0.5 through conventional reactions, achieves an ultrahigh hydrogen yield per photon of 1.28 through the unusual reactions. We demonstrated that such defect engineering enables hole-driven CO oxidation at the Pt-
T
i
O
2
interface to occur, which opens up room-temperature alcohol decomposition on Pt nanoparticles to
H
2
and adsorbed CO, accompanying with electron-driven proton reduction on Pt to
H
2
.