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.