A 20-core copper(<scp>i</scp>) nanocluster as electron–hole recombination inhibitor on TiO2 nanosheets for enhancing photocatalytic H2 evolution

For the design of atom-precise copper nanoclusters, besides the exploration of their aesthetic cage-like architectures, their structural modulation and potential applications are being extensively explored. Herein, an atom-precise 20-core copper(I)-alkynyl nanocluster (UJN-Cu20) protected by ethinyloestradiol ligands issynthesized. By virtue of outer-shell hydroxyl groups, UJN-Cu20 could be uniformly modified on the surface of TiO2 nanosheets via hydrogen bonding interactions, thus forming an efficient nanocomposite photocatalyst for hydrogen evolution. By constructing a Z-scheme heterojunction, the photocatalytic hydrogen evolution activity of the nanocomposite (13 mmol g−1 h−1) significantly improved as compared to that of TiO2 nanosheets (0.4 mmol g−1 h−1). As a narrow bandgap cocatalyst, UJN-Cu20 is confirmed to effectively inhibit the electron–hole recombination on the surface of the TiO2 nanosheet, which provides a new concept for the design of copper cluster-assisted effective photocatalysts.