Potential of two-dimensional AgAlP2Se6 monolayer for high-efficiency photocatalytic hydrogen production

In recent years, two-dimensional (2D) photocatalytic materials have garnered significant attention from researchers because of their high specific surface area and numerous active sites for photocatalytic reactions. However, many 2D photocatalytic materials exhibit low photogenerated carrier mobility and easy recombination of photogenerated electron-hole pairs, leading to poor photocatalytic performance. In this study, we propose and investigate AgAlP₂Se₆ monolayers theoretically for the first time. Through first-principle calculations, we find that AgAlP₂Se₆ monolayers possess good mechanical, thermal, and kinetic stabilities and exhibit a high carrier utilization rate. The electron mobility of the AgAlP₂Se₆ monolayer is 14.77 times higher than the hole mobility. This significant mobility difference helps to inhibit the recombination of electron-hole pairs, thereby improving photocatalytic efficiency. The solar-to-hydrogen conversion efficiency (STH) reaches 18.10 %, significantly exceeding the critical value (10 %) for the commercial application of photocatalytic water decomposition. Therefore, we predict that AgAlP₂Se₆ monolayers are a promising photocatalytic material capable of playing a significant role in photocatalytic water decomposition and other fields.