Green Approach for Metal Oxide Deposition at an Air–Liquid–Solid Triphase Interface with Enhanced Photocatalytic Activity

Bioinspired superhydrophobic substrates have been used in many scientific and technological areas. These substrates can trap atmosphere-linked air pockets at the solid-liquid interface, offering an opportunity to address the oxygen-deficit problem in many reaction systems. Herein, we addressed the oxygen-deficit problem in metal oxide electrochemical deposition by using a triphase electrode possessing an air-liquid-solid joint interface. Oxygen in the interface is directly available from the air phase for sufficient OH - production via oxygen cathodic reaction, thereby offering us a green approach to fabricate two-dimensional mesoporous ZnO nanoarrays over a wide range of current densities. Further, because metal oxides are deposited at the triphase interface, sufficient O 2 , a natural electron scavenger required in photocatalytic reaction to suppress the recombination of photogenerated electron-hole pairs, can be directly supplied, and we demonstrated their enhanced photocatalytic reaction kinetics in water remediation. The present work highlights a powerful interface-engineering strategy for fabricating metal oxides with unprecedented photocatalytic ability.