Controllable nitridation of Ta2O5 in molten salts for enhanced photocatalysis

Pyrolysis of the Ta2O5/melamine mixture in molten chlorides is herein demonstrated as a facile and controllable method to nitridize and functionalize Ta2O5. The influence of the stoichiometry and composition of Ta2O5/melamine in molten salts on the nitridation process is rationalized to ensure the controllable preparation of Ta3N5 and Ta3N5/TaON. The characterization results, including scanning electron microscopy, transmission electron microscopy, elemental mapping, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy, all confirm the existence of the Ta3N5/TaON heterojunction, in which the TaON nanoparticles are closely anchored to the Ta3N5 nanorods. Benefiting from its composition and structure, the Ta3N5/TaON composites show enhanced photocatalytic activity for the degradation of methylene blue. The present study highlights that the molten salt method using a solid nitrogen source can be a new technique for rationalizing the design of nitrides and oxynitrides.