Unusual Charge Distribution on the Facet of a SrTiO 3 Nanocube under Light Irradiation

Spatial charge separation has already been realized between different facets of a single crystal. However, how the photogenerated charges distribute on one facet of a single crystal is still unknown. In this work, we found that the distribution of photogenerated charges on a SrTiO 3 nanocube varies with the light intensity. Photogenerated holes tend to transfer to the edges and corners of the crystal under weak illumination, indicating that a spatial charge separation takes place on the same facet of the SrTiO 3 nanocube. Based on this effect, oxidation and reduction cocatalysts can be respectively photodeposited on the edges and central areas of one facet. The separated dual-cocatalysts lead to a remarkable enhancement in photocatalytic overall water splitting. These findings reveal that the spatial charge separation can happen even on the same facet.