Two-dimensional β-PdSeO3 monolayer as a high-efficiency photocatalyst for solar-to-hydrogen conversion

Abstract

Recently, PdSeO₃ nanosheets have been identified to be a high-performance two-dimensional photocatalyst for water splitting in both theory and experiments. Herein, by means of first-principles calculations, we show that a monolayer of another phase of PdSeO₃ (referred to herein as β-PdSeO₃ monolayer) exhibits great potential for solar-to-hydrogen conversion. Structural analyses demonstrate that the β-PdSeO₃ monolayer can be exfoliated from its bulk phase due to a small cleavage energy of 0.41 J m⁻², and it is kinetically and thermodynamically stable. The β-PdSeO₃ monolayer is a semiconductor with a direct band gap of 2.25 eV, and its band edge positions perfectly straddle the redox potentials of water. In addition, the photoexcited electrons of the β-PdSeO₃ monolayer generate a favorable driving force for facilitating the hydrogen evolution reaction. Specifically, the solar-to-hydrogen efficiency of the β-PdSeO₃ monolayer (12%) is much higher than those of a previously reported PdSeO₃ monolayer (1.84%) and g-C₃N₄ (3.2%) at the same theoretical level. Desirable electronic properties and efficient light utilization make the β-PdSeO₃ monolayer a promising candidate for photocatalytic water splitting.