In situ oxidative growth to form compact TiO₂–Ti₃C₂ heterojunctions for photocatalytic hydrogen evolution

Solar photocatalytic hydrogen production shows promise in addressing global energy and environmental concerns. The limited efficiency of photocatalysts is mainly due to ineffective separation and transfer of photogenerated charges. To improve this, we enhance the TiO₂–Ti₃C₂ heterojunction by in-situ oxidation through interfacial engineering, resulting in a more compact composition. Subsequently, we anchor single-atom Pt at the TiO₂–Ti₃C₂ interface through photo-Ti₃C₂ reduction. The in-situ growth of TiO₂ on Ti₃C₂ introduces an interfacial driving force for carrier separation and provides a channel for electron transfer from TiO₂ to Ti₃C₂. This further facilitates transfer onto Pt, shortening the migration distance and enhancing the photocatalytic efficiency. The best Pt/TiO₂–Ti₃C₂ composite demonstrates an impressive hydrogen precipitation efficiency of 767 μmol g⁻¹ h⁻¹, surpassing TiO₂ and Pt/TiO₂ by factors of 12 times and 1.46 times, respectively. Furthermore, we developed a higher efficiency photocatalyst using the molten salt method to avoid the risks associated with conventional hydrofluoric acid etching. This research opens up new possibilities for the preparation of MXenes interface-modified catalysts, offering a valuable avenue for future exploration in the field.