Freestanding single layers of non-layered material γ-Ga2O3 as an efficient photocatalyst for overall water splitting

Abstract

Single-layered nanosheets, as an emerging class of new materials with intriguing properties for potential applications in optoelectronics and catalysis, have been widely investigated in recent years. However, these nanosheets were only confined to the layered materials with out-of-plate weak van der Waals bonds, and for non-layered materials, it is almost impossible to achieve single-layered nanosheets through the exfoliation procedure. Here, we fabricated freestanding single-layered nanosheets of the non-layered material γ-Ga₂O₃ with unprecedented thickness (∼1.25 nm) by a facile hydrothermal method without using any kind of shape control agents. The structural stability of single-layered γ-Ga₂O₃ nanosheets originates from the surface distortion and hydroxyl group passivation. The prepared single-layered γ-Ga₂O₃ nanosheets can enhance the photocatalytic efficiency of water splitting and durably photocatalyze overall water splitting into hydrogen and oxygen. For comparison, the common bulk γ-Ga₂O₃ samples were inactive for oxygen evolution in the same case. This work opens the door for extending atomically thick 2D nanosheets to non-layered compounds and holds promise for developing a series of unprecedented excellent properties.