Novel Heterostructure as a H2-Evolving Photocatalyst Boosting the Z-Scheme Overall Water Splitting Performance under Visible Light Irradiation

Abstract

Tantalum nitride (Ta₃N₅) has been widely investigated as an extremely promising photocatalyst or photoanode for solar water splitting, but its performance is blocked by inefficient charge separation regardless of using a one-step or two-step excitation method. Here, we demonstrate significantly enhanced proton reduction on the particulate Ta₃N₅ photocatalyst with an effort for the promotion of charge separation via forming a solid solution-based heterostructure composite. One-pot nitridation was adopted to synthesize this novel heterostructure, which is composed of Ta₃N₅ and BaZrO₃–BaTaO₂N solid solution. The as-obtained composite (BaZrO₃–BaTaO₂N/Ta₃N₅) is found to exhibit superior charge separation and transfer ability compared with Ta₃N₅ and BaZrO₃–BaTaO₂N. As a result, the visible-light-driven Z-scheme overall water splitting (OWS) activity using the optimal BaZrO₃–BaTaO₂N/Ta₃N₅ composite as the H₂-evolving photocatalyst can be promoted by about 20 times. This work not only gives the first example to fabricate heterostructures based on solid solution for enhanced charge separation but also offers a new avenue to improve the photocatalytic OWS performance of Ta₃N₅.