Dual interfacial electric fields in black phosphorus/MXene/MBene enhance broad-spectrum carrier migration efficiency of photocatalytic devices

The formation of interfacial electric fields using semiconductors/co-catalysts can effectively improve the carrier migration efficiency of photocatalytic devices. Herein, an ultrathin 2D/2D/2D black phosphorus/MXene/MBene (denoted as BP/Ti3C2/MoB) ternary heterojunction with enhanced charge transfer is designed using dual interfacial electric fields. The dual interfacial electric fields formed by BP/Ti3C2 and Ti3C2/MoB effectively accelerate the photogenerated carrier transfer, change the position of the d-band center of Ti atoms, lower the energy level of the antibonding state, and enhance the adsorption effect of the H∗ active species, which ultimately leads to the significant enhancement of the photocatalytic activity. The results show that the optimum visible-light-induced H2 evolution rate of BP/Ti3C2/MoB is 8,624 μmol g−1 h−1, which has a very high enhancement factor (∼1,563%) compared to the pure BP. The charge-transfer pathways and photocatalytic mechanism are further elucidated by some state-of-the-art spectroscopic characterizations and theoretical calculations.