Construction of Ti3C2 MXene/O-doped g-C3N4 2D-2D Schottky-junction for enhanced photocatalytic hydrogen evolution

Abstract construction of the Schottky-junction is considered to be a valid route to boost the spatial charge separation and transfer of the photocatalytic system. Herein, two-dimensional (2D) O-doped g-C3N4 nanosheets were prepared by an annealing route, and then a 2D/2D Ti3C2 MXene/O-doped g-C3N4 Schottky-junction was fabricated using an in-situ electrostatic assembly of negatively charged Ti3C2 MXene and positively charged O-doped g-C3N4 nanosheets. The as-prepared Ti3C2 MXene/O-doped g-C3N4 Schottky-junction exhibited almost two times enhanced hydrogen evolution (25124 μmol/g/h) in comparison to pristine O-doped g-C3N4 (13745 μmol/g/h) and Ti3C2 MXene/pristine C3N4 (15573 μmol/g/h). Based on fully characterizations and theory calculation, the enhanced photocatalytic performance could be attributed to the synergy effect of intimate 2D/2D interfacial contact and the construction of Schottky-junction, which result in the short charge transport distance from HCN to Ti3C2 MXene and efficient separation of the photo-generated charge. This study will provide new insight into developing 2D/2D Schottky-junction photocatalysts for the solution of the energy crisis.