Growth of BaTaO2N-BaNa0.25Ta0.75O3 Solid Solution Photocatalyst for Visible Light-Driven Z-Scheme Overall Water Splitting

BaTaO2N with intense visible light absorption has been demonstrated as a promising photocatalyst for Z-scheme overall water splitting, whereas the photocatalytic activity of BaTaO2N is still restricted by strong charge recombination at structural defects. Here, we present the direct growth of BaTaO2N- BaNa0.25Ta0.75O3 solid solution from a lattice-matched BaNa0.25Ta0.75O3 precursor through volatilization of Na species during a nitridation process. This method promotes the direct phase transformation from BaNa0.25Ta0.75O3 to BaTaO2N to inhibit the formation of defect states. As a result, the as-obtained BaTaO2N- BaNa0.25Ta0.75O3 solid solution shows greatly enhanced activity compared to the conventional BaTaO2N, regardless of photocatalytic H2 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.