Triphase Photocatalytic CO Reduction over Silver-Decorated Titanium Oxide at a Gas-Water Boundary.

Photocatalytic CO reduction reaction (CO RR) is an attractive process to convert CO into valuable chemicals. But this reaction is often restricted by the poor mass transfer of CO in the liquid phase. Here, we have developed a triphase photocatalytic CO RR system by supporting Ag-decorated TiO nanoparticles at a gas-water boundary with hydrophobic-hydrophilic abrupt interfacial wettability. Such a triphase system allows the rapid delivery of gas-phase CO to the surface of photocatalysts while maintaining an efficient water supply and uncovered active sites. Ag-TiO supported at the gas-water boundary showed a CO reduction rate of 305.7 μmol g  h , without hole scavengers, approximately 8 times higher than the nanoparticles dispersed in the liquid phase. Even using diluted CO (10 %) as the reactant, the CO RR activity was superior to most reported Ag-TiO based photocatalysts using pure CO . The findings provide a general strategy to promote the interfacial CO mass transfer to improve photoactivity and selectivity.