Regulation of a rutile/anatase TiO2 heterophase junction in situ grown on Ti3C2Tx MXenes with remarkable photocatalytic properties

Abstract

TiO₂(rutile–anatase, R–A)/Ti₃C₂T_x heterophase junction (HPJ)–Schottky junction (SHJ) composites oxidized in situ by Ti₃C₂T_x MXenes were synthesized via a one-step hydrothermal method using Ti₃C₂T_x MXenes as the Ti source and water as the solvent. There was no need for the induction and oxidation of other chemical reagents in the reaction, the reaction conditions were green and non-toxic, and the experimental operation was simple. The number of TiO₂(R–A) HPJs and Ti₃C₂T_x SHJs can be regulated by changing the reaction temperature and time. The optimized photocatalyst exhibited a large number of TiO₂(R–A) HPJs attached to the surface of Ti₃C₂T_x. TiO₂(R–A)/Ti₃C₂T_x-200 °C-15 h showed a photocatalytic N₂ reduction efficiency of 59.35 μmol L⁻¹ h⁻¹. The photoelectrochemical properties of the photocatalyst indicated that TiO₂(R–A) HPJs and Ti₃C₂T_x SHJs have synergistic effects on the separation of photogenerated charges. Under the condition of photoexcitation, the photogenerated charge generated by TiO₂ was separated at the rutile/anatase interface and transferred in the form of type II heterojunctions. Owing to the effect of Ti₃C₂T_x SHJs, it can quickly transfer and store holes on TiO₂. Thus, the photocatalyst had remarkable photogenerated charge separation efficiency; TiO₂(R–A)/Ti₃C₂T_x-200 °C-15 h had the strongest photocatalytic performance. This provides a new way to rationally design homogeneous heterojunctions for photocatalytic applications.