A two-dimensional superatomic B₆O₂ monolayer for photocatalytic water splitting

Two-dimensional (2D) transition metal dichalcogenides have attracted considerable attention as photocatalysts due to their large specific surface area, tunable bandgaps, and strong light-matter interactions. In this work, we design a T-MoS₂-like 2D superatomic B₆O₂ monolayer, in which octahedral B₆ superatomic units are vertex-linked by oxygen atoms to form a robust covalent framework. Chemical bonding analysis reveals that the stability originates from the covalent B-O bonds and the superatomic B₆ core with the 14-electron (Wade's) rule. Featuring remarkable light absorption coefficients, high carrier mobilities and a strain-adjustable band structure, the B₆O₂ monolayer emerges as a promising candidate for UV-driven water splitting under acidic (pH = 0), neutral (pH = 7) and alkaline (pH = 8) conditions. This work offers a superatomic assembly strategy for engineering 2D materials with tailored photocatalytic functionalities.