Platy BaTaO₂N Crystals Fabricated from K₂CO₃–KCl Binary Flux for Photocatalytic H₂ Evolution

The performance of particulate photocatalysts for solar H2 production highly depends on the unique morphology and tailored shape. Herein, we successfully fabricated a highly crystalline BaTaO2N crystal with a plate-like structure from a K2CO3–KCl binary flux under a nitridation atmosphere. The fabricated platy BaTaO2N was characterized, and the results as well as formation mechanism were discussed accordingly. Owing to the generation of oxo-complex [TaO3]− by the assistance of CO32– and the lattice match of the BaTaO2N (111) plane with the Ba5Ta4O15 (001) plane, the platy BaTaO2N crystals with well-developed {111} facets were formed via the simultaneous formation and transformation of Ba5Ta4O15. Upon optimization of the molar ratio of K2CO3 and KCl, an excellent photocatalytic performance for H2 evolution was obtained at the molar ratio of 20/80 due to the plate-like structure and high crystallinity of the BaTaO2N photocatalyst. This finding provides a facile approach for the fabrication of shape-controlled and highly crystallized (oxy)nitride photocatalysts aimed at efficient solar H2 production.