Photocatalytic Z-scheme overall water splitting for hydrogen generation with Sc2CCl2/ML (ML=MoTe2, Hf2CO2) heterostructures

Direct Z-schemes for photocatalytic overall water splitting for hydrogen generation are constructed for Sc2CCl2/ MoTe2 and Sc2CCl2/Hf2CO2 heterostructures on the basis of the calculated band alignment and built-in electric field. Solar-to-hydrogen efficiency (eta ' STH), which is evaluated using the overpotentials of the band edges and band gaps, can reach 22.09 % for Sc2CCl2/MoTe2 and 19.07 % for Sc2CCl2/Hf2CO2. Tensile strains have little effect on eta ' STH. Compressive strains substantially increase the eta ' STH of Sc2CCl2/MoTe2 and boost that of the Sc2CCl2/Hf2CO2 heterostructure only slightly. Nonadiabatic dynamics simulations reveal that the lifetime of the photogenerated electron in one of the stacking patterns of Sc2CCl2/MoTe2 is much larger than that of the other configurations, indicating that the reduction ability of the electron is well protected. However, the interlayer electron-hole recombination in Sc2CCl2/MoTe2 is faster than that in Sc2CCl2/Hf2CO2, implying that the Z-schemes with the former are more efficient than the Z-schemes with the latter. The hydrogen and oxidation evolution reactions with the two heterostructures are thermodynamically feasible but the reactions cannot proceed spontaneously. These findings provide a helpful guide for the development of photocatalytic materials for photocatalytic hydrogen generation from overall water splitting based on the title heterostructures.