Two-dimensional trilayer heterostructures with cascade dual Z-schemes to achieve efficient hydrogen evolution reaction

Abstract

Cascade dual Z-schemes for photocatalytic overall water splitting for hydrogen production are constructed for trilayer Bi/HfSeTe/ZrSe₂, Bi/HfSeTe/ZrSe₂, and InAs₃/HfSeTe/ZrSe₂ heterostructures. Electronic properties are studied by first-principles calculations, and the photoexcited carrier pathway is explored by nonadiabatic molecular dynamics simulations. The arrow-up, arrow-down, and cascade arrangement of band alignments for the Bi/HfSeTe/ZrSe₂ and InAs₃/HfSeTe/ZrSe₂ heterostructures are explored, and those for the HfSe₂/ZrSe₂/HfSe₂ and ZrSe₂/HfSe₂/ZrSe₂ sandwich heterostructures are also considered for comparison. The solar-to-hydrogen efficiency of 22.08% for the bilayer HfSeTe/ZrSe₂ heterostructure can be raised to 40.52%, 39.47%, and 41.04% by the cascade dual Z-schemes with Bi/HfSeTe/ZrSe₂, Bi/HfSeTe/ZrSe₂, and InAs₃/HfSeTe/ZrSe₂. They can further be boosted to 41.53%, 41.12%, and 43.57% under 1%, 1%, and −2% biaxial strains, respectively. The nonadiabatic molecular dynamics simulations reveal that the activity of the photogenerated carriers can be well protected. Moreover, the Gibbs free energy changes demonstrated that the hydrogen and oxygen evolution reactions driven by Bi/HfSeTe/ZrSe₂ can spontaneously proceed. Therefore, the cascade dual Z-scheme provides an effective way to develop highly efficient photocatalysts for hydrogen generation from overall water splitting.