Controlled Decoration of Divalent Nickel onto CdS/CdSe Core/Shell Quantum Dots to Boost Visible-Light-Induced Hydrogen Generation in Water.

The search for a low-cost, noble-metal-free cocatalyst to replace expensive Pt for hydrogen (H2 ) photogeneration in water has become a hot research topic, and among these, Ni-based cocatalysts are promising and highly desired. Developing new strategies and protocols to obtain Ni-based cocatalysts with high activity is therefore vitally important. Herein, we develop a new method to efficiently decorate divalent Ni onto pre-synthesized CdS/CdSe core/shell quantum dots (QDs). The concentration of Ni on the QDs can be easily tuned by varying the amount of the Ni precursor introduced during the synthesis. Further analyses reveal that Ni2+ can be strongly decorated onto QDs. Impressively, the Ni-decorated QDs displayed a significantly enhanced H2 photogeneration performance as compared to the two components prepared separately. Through the optimization of the Ni concentration on the QDs, the turnover frequency (TOF) with respect to Ni and quantum yield ( Φ H 2 ) at 520 nm for H2 evolution from water could reach 322 h-1 and 12.3 %, respectively. A possible mechanism has also been proposed and discussed in detail.