Bifunctional Photocatalysis Toward Efficient NO_x Removal Performance and Water Splitting Activity: A Case of TiO₂/g-C₃N₄

Studies about emissions reduction and treatment, and renewable energy generation are sustainable development goals of the United Nations. Therein, photocatalysts have emerged as highly attractive multifunctional materials due to their versatile applications in environmental remediation and energy production. In this study, a bifunctional photocatalyst, TiO₂/g-C₃N₄, was synthesized for the purpose of NO_x removal and water splitting. Various weight ratios of commercially available TiO₂ were combined with g-C₃N₄ synthesized through a pyrolysis method. The findings demonstrate that the 10%-TiO₂/g-C₃N₄ composite exhibited a notably high NO removal rate of 48.34% and minimal NO₂ yield compared to pure g-C₃N₄. The incorporation of TiO₂ onto g-C₃N₄ induced bandgap restructuring, resulting in a significant enhancement in photocurrent density, with a maximum increase of 25 μA cm⁻² at 1.23 V. Moreover, the combination of g-C₃N₄ with 10% TiO₂ exhibited promising electrocatalytic potential for the oxygen evolution reaction, as indicated by an overpotential of 0.44 V. Overall, the utilization of bifunctional photocatalysis with TiO₂/g-C₃N₄ holds great promise as an effective approach for both NO_x removal and water splitting applications. This combination offers potential solutions for addressing environmental challenges and advancing renewable energy technologies.