Designing of g-ZnO/HfZrCO₂ vdW Heterostructure for Sunlight-Driven Water Splitting Photocatalyst

In this paper, we designed g-ZnO/HfZrCO 2 van der Waals heterostructures (HS) by stacking g-ZnO and HfZrCO 2 monolayers together to search sunlight-driven water-splitting photocatalyst. Then we selected the two most stable structures between them, AA-HS and AK-HS, for further study. The AK-HS shows a type-I band arrangement, which is not suitable as a photocatalyst for water splitting; while the AA-HS belongs to a type-II band alignment semiconductor. To regulate its band structure, different biaxial strains parallel to the stacking layers from −2% to 2% are applied on AA-HS. The results show AA-stacking HS under compressive strains exhibit typical type-II band arrangement with a staggered gap. Further investigations show that the band edges of AA-HS under a compressive strain of 0.5% meet the requirement of water redox potentials at PH 0. In addition, the absorption coefficients of AA-HS under the compressive strain of 0.5% were calculated, and the results it has good optical absorption of sunlight. The excellent photoelectric and catalytic properties make the AA-HS under compressive strain of 0.5% as a potential sunlight-driven catalyst for water splitting in a strong acid environment.