Coupling of surface oxygen vacancy and 2D structure of Aurivillius-phase CaBi2Ta2O9 nanoplates for enhanced photocatalytic H2 production

Solar-driven water splitting over semiconductor-based photocatalyst is considered as one of the most promising approaches to address the looming energy shortage and environmental pollution. However, most of photocatalysts still suffer from low hydrogen production activity owing to the poor photo-absorption ability, rapid recombination of photo-generated charge carriers and insufficient surface active sites. Herein, we tackle these challenges by introducing surface oxygen vacancies (OVs) on the layered Aurivillius-phase perovskite CaBi2Ta2O9 nanoplates via a combined high-temperature molten salt and post-reduction process. Theoretical and experimental results demonstrate that the rich OVs anchored on the surface of CaBi2Ta2O9 nanoplates not only extend the photo-responsive range to visible region, improve the separation efficiency of photo-induced charge carriers, but also enrich the surface reactive sites. As a result, under a 300 W xenon lamp irradiation, the OVs-abundant CaBi2Ta2O9 nanoplates exhibit an outstanding H2 production rate, which is 7.4 times higher than that of the bulk CaBi2Ta2O9 in the absence of OVs. Our study provides a general and efficient coupling strategy to advance the H2 production performance of layered perovskite oxide for solar energy conversion.