Two-dimensional g-C_6N_6/SiP-GaS van der Waals heterojunction for overall water splitting under visible light

摘要

? 2022 Hydrogen Energy Publications LLCThe energy crisis caused by the decrease of fossil fuels and the environmental pollution problems related to combustion can be resolved through the green technology of photocatalytic water splitting to produce hydrogen. A novel g-C6N6/SiP-GaS van der Waals heterojunction is designed and its structural, optoelectronic and photocatalytic properties are systematically investigated by using the first-principles method. The results indicate that the g-C6N6/SiP-GaS heterojunction is a type-Ⅱ heterojunction and the band edge straddles the redox potential of water splitting. The g-C6N6/SiP-GaS heterojunction exhibits good optical absorption in the visible-light range. It is worth noting that the optoelectronic properties and thermodynamic feasibility of the heterojunction can be modulated by the biaxial strain. Interestingly, all the optical absorption, OER and HER can be effectively improved under the strain of ?4. The work supplies a strategy for the design and making of novel heterojunction for a highly effective photocatalyst in water splitting.