Two-Dimensional Li-Based Ternary Chalcogenides for Photocatalysis

Motivated by fundamental interest and practical applications, the investigations of two-dimensional photocatalysts are fascinating subjects in clean energy. Herein, we propose that two-dimensional Li-based ternary chalcogenides LiXY₂ (X = Al, Ga, In; Y = S, Se, Te) have intrinsic polarization and direct band gaps. Our results show that LiXY₂ materials possess optical absorption spectra covering the visible and ultraviolet range. We show that these materials possess extremely high electron mobility (∼10³ cm² V^-1 s^-1), providing great potential in overall water splitting. Furthermore, LiAlS₂ and LiGaS₂ can facilitate overall water splitting regardless of their energy gaps because of the large differences of surface electronic potentials of LiXY₂. Importantly, it is feasible to exfoliate the layered LiAlTe₂ from its bulk counterpart in experiments. Our findings open an exotic pathway to realizing promising photocatalytic applications in two-dimensional ternary materials.