In Situ Conversion of Ti₃C₂ MXene to Sandwich Ti₃C₂/R-TiO₂ for Promoted Photocatalytic Hydrogen Production

Ti3C2 MXene has been extensively studied in the field of photocatalytic hydrogen production since its discovery due to the large specific surface area and adjustable surface groups. However, the weak interaction at the interface of Ti3C2-based composites leads to a high energy barrier, which is not conducive to carrier transport. Herein, we propose the construction of a sandwich Ti3C2/R-TiO2 composite photocatalyst by in situ growing rutile TiO2 (R-TiO2) nanoneedles in Ti3C2 MXene through NaOH oxidation treatment and the microwave hydrothermal method. This in situ synthesis can make Ti3C2 MXene and TiO2 nanoneedles closely link together, which is conducive to carrier transport and material stability. The best Ti3C2/R-TiO2 composite achieves an excellent hydrogen production rate of 1.62 mmol g–1 h–1, as endowed by the 2D nanosheet-constructed sandwich structure, an increased specific surface area, and improved charge carrier separation and transport.