Synthesis of NaNbxTa1−xO3/g-C3N4 composite photocatalyst for enhanced removal of organic dye

Water pollution has received much attention and constructing efficient catalysts to photodegrade the pollutants is a promising method. Herein, we reported that a novel composite catalyst, NaNb x Ta 1−x O 3 /g-C 3 N 4 , exhibited high efficiency to degrade the model pollutant, methylene blue (MB), in ultraviolet light. The optimal catalyst was NaNb 0.75 Ta 0.25 O 3 /g-C 3 N 4 (1:9), which degraded 99.6% of MB (10 mg/L) after 180 min of reaction. The superior photocatalytic activity was attributed to the formation of the Z-scheme heterojunction, which could suppress the recombination of the photogenerated electron-hole pairs and protect the high redox potentials simultaneously. Hydroxyl radicals ( . OH) and superoxide radicals ( . O 2 - ) were found to be the dominant active free radicals in the reaction process and a possible photocatalytic mechanism over the catalyst was proposed accordingly. This work provides an efficient direction to fabricate composite photocatalysts and helps to overcome the shortcomings of a single catalyst.