Suppressing photocarrier recombination in anatase TiO2 nanoplates via thickness optimization for enhanced photocatalytical H2 generation

Abstract Exposure of a specific crystal facet is critical to maximizing the photocatalytic performance of catalysts, which makes two-dimensional (2D) materials an attractive candidate for photocatalysis. Optimizing the 2D microstructure such as thickness to suppress the photocarrier recombination is essential to develop high performance photocatalysts. Recently developed nanosheet-seeding technique enables to synthesize 2D materials with a specific crystal facet exposed, which offers an opportunity to optimize the structural configuration of materials. In this study, anatase TiO2 nanoplates with different thickness from ~25 to ~ 120 nm were fabricated by using the nanosheet-seeding technique, and effect of the thickness on the photocatalytic H2 generation was investigated. The results demonstrate that the thickness mainly influences the charge separation process, and there exists a volcano-shaped correlation between the thickness and the photocatalytic H2 production rate. The optimal TiO2 nanoplates with the thickness of ca. 50 nm exhibit the best photocatalytic H2 evolution activity.