Development of g-C3N4-TiO2 heterojunction for photocatalytic degradation of rhodamine B dye and production of hydrogen.

Organic dyes are released into wastewater from various industries and pose a significant risk to living organisms. The eradication of organic dyes from aqueous systems by photocatalysis has received the attention of researchers promoting environmental sustainability. In this study, g-C3N4, TiO2, and their composites in a 1 : 1, 1 : 2, and 2 : 1 ratio were prepared and characterized. The prepared composites were tested for the catalytic elimination of aqueous rhodamine B dye and for the production of hydrogen using an aqueous solution of triethanolamine (TEOA) under visible light. It was noticed that ∼65, 22, 87, 100, and 78% of the rhodamine B dye (50 ppm, 35 mL) degraded after 2 h reaction with 35 mg g-C3N4, TiO2, and their composites in a 1 : 1, 1 : 2, and 2 : 1 ratio, respectively. The visible light-assisted production of hydrogen from water vapor splitting was 110, 32, 2597, 3463, and 1791 µmol g-1 with g-C3N4, TiO2, and their composites in a 1 : 1, 1 : 2, and 2 : 1 ratio, respectively. The integration of g-C3N4 with TiO2 significantly boosted the catalytic role due to the synergistic interaction between the individual constituents. The prepared composite exhibited similar photocatalytic activity in three consecutive cycles of rhodamine B degradation and four consecutive cycles of hydrogen production, indicating the highly stable nature of the fabricated composite. It was concluded that g-C3N4-TiO2 can be used as an effective catalyst in remediation of wastewater contaminated with organic pollutants and the production of hydrogen in visible light.