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 TiO 2 –Ti 3 C 2 heterojunction by in-situ oxidation through interfacial engineering, resulting in a more compact composition. Subsequently, we anchor single-atom Pt at the TiO 2 –Ti 3 C 2 interface through photo-Ti 3 C 2 reduction. The in-situ growth of TiO 2 on Ti 3 C 2 introduces an interfacial driving force for carrier separation and provides a channel for electron transfer from TiO 2 to Ti 3 C 2. This further facilitates transfer onto Pt, shortening the migration distance and enhancing the photocatalytic efficiency. The best Pt/TiO 2 –Ti 3 C 2 composite demonstrates an impressive hydrogen precipitation efficiency of 767 μmol g−1 h−1, surpassing TiO 2 and Pt/TiO 2 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. • Ti 3 C 2 MXene was synthesized by F-free molten salt method. • TiO 2 –Ti 3 C 2 composites were successfully synthesized by in situ oxidation method. • Single-atom Pt interface engineered Pt–O electron transfer channel to shorten the charge migration distance. • TiO 2 –Ti 3 C 2 heterojunction interface Ti– O –Ti bridge promotes rapid electron transfer and separation. • Single-atom and heterojunction interface engineering synergistic effect to promote photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]