Arsenene/PtO2 heterojunction: a potential Z-scheme photocatalyst with tunable electronic properties and efficient catalytic activity

This paper systematically investigates the geometric composition, electronic behavior and photocatalytic performance of arsenene/PtO2 heterojunctions through computational studies grounded in the principles of density functional theory (DFT). This study demonstrates that the arsenene/PtO2 heterojunction exhibits a typical type II band alignment with an indirect bandgap narrowed to 1.43 eV. The Z-scheme charge transfer mechanism is more conducive to the separation of photogenerated carriers to promote catalytic reactions. Moreover, the band edge positions of the arsenene/PtO2 heterojunction are capable of surpassing the redox potential of water across a range of pH conditions. Hydrogen is generated on the conduction band (CB) of arsenene during the reduction process, while the valence band (VB) of PtO2 hosts the oxidation process that produces oxygen, collectively driving water splitting. At the same time, under compressive and tensile strains of 0-6%, the band edge alignment of the arsenene/PtO2 heterojunction still meets the requirements for photocatalytic water splitting. Moreover, the arsenene/PtO2 heterojunction not only exhibits enhanced light absorption capabilities compared to the individual monolayer materials but also demonstrates improved light absorption performance under tensile strain, and its solar-to-hydrogen (STH) efficiency reaches 47.29%. Consequently, the arsenene/PtO2 heterojunction is expected to become a strong candidate material for the next generation of photocatalysts.