Ultra-fine Cu clusters decorated hydrangea-like titanium dioxide for photocatalytic hydrogen production

Hydrogen, with the merits of zero emissions and high energy density, is one of the promising green energy sources. Seeking for high efficiency and low-cost catalysts is one of the key issues for hydrogen evolution and its practical applications. Nano-structured metal co-catalysts are widely used to improve the photocatalytic performance via surface electronic structure/properties optimization of the catalyst. Herein, we report ultra-fine (~ 1 nm) Cu clusters decorated hydrangea-like TiO2 systems for photocatalytic hydrogen evolution. The pristine hydrangea-like TiO2 support shows a promising performance of hydrogen evolution (1.8 mmol·h−1·g−1), which is ~ 10.7 times higher than that of the commercial P25 (168 μmol·h−1·g−1). After ultra-fine Cu clusters decoration, a maximal hydrogen evolution performance (3.7 mmol·h−1·g−1) is achieved in the optimized system 6Cu–TiO2 (6 wt%). Experimental and theoretical studies demonstrate that the ultra-fine Cu clusters decoration could promote the charge separation and transfer process effectively. The Cu clusters also act as reaction sites for reduction of H2O to H2. These results are of great importance for the study of Cu-based co-catalyst systems and also shed light on the development of other non-noble metal co-catalysts in photocatalysis hydrogen evolution.