Selenium-enriched amorphous NiSe1+ nanoclusters as a highly efficient cocatalyst for photocatalytic H2 evolution

Exploiting and fabricating of novel non-noble metal cocatalysts with abundant active sites is highly required to boost the photocatalytic performance. Herein, selenium-enriched amorphous NiSe1+x nanoclusters (a-NiSe1+x) as a novel cocatalyst were rationally integrated with the TiO2 to greatly boost its hydrogen-generation rate via a simple photoinduced deposition route. It was interesting to find that in comparison with the crystalline nickel selenide (c-NiSe), the a-NiSe1+x evidently displayed more unsaturated active Se atoms because of its highly irregular arrangement structure and small particle size (0.5–2 nm). Photocatalytic results revealed that the a-NiSe1+x nanoclusters could significantly improve the hydrogen-production activity of TiO2 (4095.3 μmol h−1 g−1, AQE = 19.6%), which is higher than that of pristine TiO2 and c-NiSe/TiO2. The outstanding performance of a-NiSe1+x/TiO2 can be attributed to the synergism of facilitated photoelectron transfer from TiO2 to a-NiSe1+x cocatalyst and excellent H2-production active site of Se atoms, which was well revealed by density functional theory (DFT) calculations and in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) measurement. Based on the above results, an enriched Se-mediated mechanism is raised for the boosted H2-generation rate of a-NiSe1+x/TiO2. Moreover, the present a-NiSe1+x can also be used as the general cocatalyst for typical g-C3N4 and CdS photocatalysts. Considering the gentle preparation, low-cost and admirable activity, the a-NiSe1+x cocatalyst would have tremendous prospects for the fabrication of advanced photocatalytic materials.