Prediction of a novel two-dimensional superatomic Cd6S2 monolayer for photocatalytic water splitting.

Two-dimensional transition metal dichalcogenides possess a significant specific surface area, adjustable bandgaps, and excellent optical absorption properties, rendering them highly conducive to photocatalytic applications. Herein, a MoS₂-like 2D superatomic Cd₆S₂ monolayer is predicted, wherein the octahedral Cd₆ superatom unit connects with S atoms via six vertices. Chemical bonding analysis reveals that the remarkable dynamic, thermal, and mechanical stability of the Cd₆S₂ monolayer results from the covalent Cd–S bonds and the 6-center 8-electron (6c–8e) delocalized bond within the Cd₆ core, which ensures the chemical octet rule for both the S atom and the Cd₆ superatom. Demonstrating notable optical absorption coefficients and a strain-tuned energy band structure, the Cd₆S₂ monolayer emerges as a viable candidate for catalyzing the solar-powered splitting of water. This work offers an alternative avenue to modify or improve the properties of 2D materials for photocatalytic applications through superatomic assembly. [ABSTRACT FROM AUTHOR]