Computational investigation of high stability and solar-to-hydrogen efficiency in two-dimensional SiP, GeP, and SnP for enhanced photocatalytic water splitting†
Abstract
Photocatalytic water splitting technology plays a pivotal role in addressing the energy crisis and environmental protection challenges. In this study, we conducted a first-principles computational investigation into the stability, electronic structures, and photocatalytic water splitting properties of three two-dimensional monolayers: SiP, GeP, and SnP. The results show that all the monolayers exhibit high mechanical, thermal, and dynamic stability across all domains. They also show semiconductor characteristics with band gaps of 2.50, 1.97, and 1.85 eV, and electron mobilities ranging from 1558.15 to 6243.65 cm2 V−1 s−1. Furthermore, these materials also possess well-aligned band edges to drive both the H+/H2 and O2/H2O reactions and exhibit a strong absorption coefficient of ∼105 cm−1, covering both ultraviolet and visible spectra. Notably, they also have moderate exciton binding energies (390–510 meV) and impressive solar-to-hydrogen efficiencies ranging from 8% to 13%. In conclusion, these three monolayers hold significant potential as novel candidates for nano-optoelectronics and photocatalytic water splitting applications.