Ultrathin 2D/2D Ti3C2Tx/semiconductor dual-functional photocatalysts for simultaneous imine production and H2 evolution

Abstract

Ultrathin 2D/2D Ti₃C₂T_x/semiconductor (CdS and Bi₂MoO₆) dual-functional photocatalysts have been constructed for the oxidative coupling of benzylamines to imines combined with H₂ generation under visible light irradiation (λ ≥420 nm). The optimal 2D/2D Ti₃C₂T_x/CdS sample exhibits high photocatalytic performance toward H₂ evolution (219.7 μmol g⁻¹ h⁻¹) and imine production (155.8 μmol g⁻¹ h⁻¹), which is 5 times and 6 times higher than that of pure CdS, respectively. In situ irradiated XPS and photoelectrochemical characterizations reveal that the enhanced photoactivity over Ti₃C₂T_x/semiconductor heterostructures can be attributed to the facilitated charge separation from the semiconductors to the Ti₃C₂T_x cocatalyst. A possible reaction mechanism is proposed based on in situ FTIR spectroscopy of benzylamine adsorption and imine product desorption and reaction intermediate detection using in situ ESR. This work provides a systematic strategy to construct ultrathin 2D/2D Ti₃C₂T_x/semiconductor heterojunctions for photocatalytic synthesis of high value-added products combined with H₂ generation.