Effect of layers on the photocatalytic hydrogen evolution in Dion-Jacobson layered-tantalum perovskites.

Tantalum-based layered perovskites have always been an interesting topic in photocatalysis, but limited information has been reported in terms of their layer factor. In this work, we have synthesized Dion-Jacobson layered perovskites (A'[An-1TanO3n+1]) of LaTaO4, KLaTa2O7, and KCa2Ta3O10 with n = 1, 2, and 3, respectively. With the modification of 1 wt% Pt co-catalysts, the photocatalytic analysis showed that the performance order of these layered perovskites with different layers is KLaTa2O7 (n = 2) > KCa2Ta3O10 (n = 3) ≫ LaTaO4 (n = 1) with both methanol and NaI as the sacrificial agents. This suggested the importance of interlayer K+ for high photocatalytic performance. We further analyzed the layered perovskites in detail by BET, photoelectrochemical analysis, Mott-Schottky, and VB-XPS test. The combined results indicated that the positions of the conduction band are the dominant factors for the photocatalytic performance of tantalum-based Dion-Jacobson layered perovskites with n = 2 and 3. This work sheds new light on the field of layered perovskites as efficient photocatalysts.