In situ fabrication of 2D/3D g-C3N4/Ti3C2 (MXene) heterojunction for efficient visible-light photocatalytic hydrogen evolution

Photocatalytic water splitting has been recognized as a hopeful route for producing hydrogen. To design a catalyst with high separation efficiency of photo-induced carriers is critical for boosting hydrogen product rate. In this work, we report an in-situ construction strategy for g-C3N4/Ti3C2 composites by one-step calcination process. And a unique 2D/3D structure was obtained through the uniform distribution of lamellar g-C3N4 on Ti3C2 surface. The photocatalytic hydrogen product rate of optimized g-C3N4/Ti3C2 composite was above six times higher than that of pristine g-C3N4 under visible light irradiation. For purpose of clarifying the potentially photocatalytic mechanism, a series of tests involving Kelvin probe measurements and the density functional theory (DFT) calculations were executed. The results confirmed that the Schottky junction between g-C3N4 and Ti3C2 efficiently restrains the recombination of photo-induced carriers. Furthermore, the excellent conductivity of Ti3C2 and the intimate interface of components corporately facilitate the electron immigration. This work provides a new approach to the fabrication of highly efficient g-C3N4/Ti3C2 composite for photoconversion applications.