Surface Reconstruction of Facet-Functionalized SrTiO3 Nanocrystals for Photocatalytic Hydrogen Evolution

The surface structure determines the surface electronic and chemical properties of semiconducting nanocrystals for efficient photocatalysis. Herein, SrTiO3 nanocrystals enclosed by {001} and {023} facets functionalized for photoreduction and photooxidation, respectively, were surface-reconstructed with a disordered overlayer created by a thermal hydrogenation process. These surface-reconstructed SrTiO3 nanocrystals showed much higher photocatalytic activities than the pristine SrTiO3, which was attributed to the enhanced charge transfer ability and accelerated oxidative reaction kinetics induced by the oxygen vacancies in disordered overlayer. Given the maintained {001} and {023} facets ensuring spatial charge separation and functioning for reduction and oxidation reactions, respectively, the surface-reconstructed SrTiO3 nanocrystals enclosed with {023} and {001} facets in appropriate ratio showed the highest photocatalytic activity for hydrogen evolution.