High-performance photocatalytic hydrogen generation and rhodamine B degradation by TiO2 modified g-C3N4 photocatalysts

Increasing industrialization and growth in the global population are driving a greater demand for clean energy and environmental sustainability. This has led to the demand for alternative renewable energy sources. Many nations cannot offer potable water to society due to the different pollutants released from industries. This study produced a novel polyvinyl alcohol (PVA)-assisted TiO 2 -g-C 3 N 4 composite using the hydrothermal method for Rhodamine B degradation and photocatalytic hydrogen generation. Pristine materials TiO 2 and g-C 3 N 4 were prepared through hydrothermal and polymerization of melamine, respectively. Advanced characterization techniques were used to explore chemical bonding, crystallite size, surface area, surface morphology, optical, and electrochemical properties. TiO 2 -g-C 3 N 4 showed a notable improvement in bandgap and surface area as compared to pristine materials. This enhancement is possibly due to the synergetic effects of the two materials. The highest degradation percentage of RhB (98.4%) and production of H 2 (16.2 mmol g -1 h -1 ) were achieved for TiO 2 -g-C 3 N 4 composite at a pH of 9, 70 mg/L catalyst load, and 10 mg/L RhB dye. Additionally, the TiO 2 -g-C 3 N 4 composite shows the maximum kinetic rate constant, which is 5.8 and 3.9-fold greater than that of TiO 2 and g-C 3 N 4 , respectively. This enhancement is possibly due to the synergetic effects of the two materials. The optimization of pH, initial dye concentration, and catalyst load was explored. Comparatively, the maximum efficiency of dye degradation and H 2 gas evolution was observed at a pH of 9, 70 mg/L catalyst load, and 10 mg/L RhB dye. The stability of the TiO 2 -g-C 3 N 4 composite from the first cycle (98%) to the six cycle (89%) was confirmed using XRD and DRS techniques. A possible mechanism of photocatalysis was proposed using the TiO 2 and g-C 3 N 4 photocatalysts.