Boost solar-to-hydrogen efficiency by constructing heterostructures with the pristine and Se/Te-doped AgInP2S6 monolayers

Abstract

To achieve high solar-to-hydrogen efficiency (η'STH), we identify the geometrical structures of seven heterostructures comprising the pristine and doped AgInP2S6 monolayers and confirm the stabilities. The electronic properties by HSE06 with dipole corrections are used to demonstrate the charge polarization and the built-in electric field in heterostructure. The direct Z-schemes for hydrogen evolution on the heterostructures are constructed based on the projected band edge potentials of each monolayer, and the corresponding s are evaluated. The results demonstrate that both doping and constructing heterostructure can significantly boost the s. Remarkably, the Se-doped AgInP2S6 monolayer promotes the from 6.41% to 12.50%, while the two configurations of the AgInP2S3Se3/AgInP2S3Te3 heterostructure raise to 17.59% and 19.88%, respectively. The corresponding total energy conversion efficiency reach 0.37% and 0.43%. Moreover, strain engineering significantly impacts with either boosting or degrading effects depending on the different strains. The highestof 31.17% can be achieved for the AgInP2S3Se3/AgInP2S3Te3 heterostructure under 4% biaxial tensile strain. The changes of −0.15–1.69 eV for the Gibbs free energies in the hydrogen evolution reactions indicate these reactions are feasible in thermodynamics. Therefore, the heterostructures based on the Se/Te doped AgInP2S6 monolayers, especially the AgInP2S3Se3/AgInP2S3Te3 one, are a potential candidate for developing high efficient photocatalysts.