Growth of BaTaO ₂ N–BaNa _0.25 Ta _0.75 O ₃ Solid Solution Photocatalyst for Visible Light-Driven Z-Scheme Overall Water Splitting

Abstract

BaTaO 2 N with intense visible light absorption has been demonstrated as a promising photocatalyst for Z-scheme overall water splitting, whereas the photocatalytic activity of BaTaO 2 N is still restricted by strong charge recombination at structural defects. Here, we present the direct growth of BaTaO 2 N–BaNa 0.25 Ta 0.75 O 3 solid solution from a lattice-matched BaNa 0.25 Ta 0.75 O 3 precursor through volatilization of Na species during a nitridation process. This method promotes the direct phase transformation from BaNa 0.25 Ta 0.75 O 3 to BaTaO 2 N to inhibit the formation of defect states. As a result, the as-obtained BaTaO 2 N–BaNa 0.25 Ta 0.75 O 3 solid solution shows greatly enhanced activity compared to the conventional BaTaO 2 N, regardless of photocatalytic H 2 evolution in the presence of methanol or Z-scheme overall water splitting. This study provides a facile method to construct (oxy)nitride-based solid solution photocatalysts with low defect density for efficient solar hydrogen production from water splitting.