Surface localization of CdZnS quantum dots onto 2D g-C3N4 ultrathin microribbons: Highly efficient visible light-induced H2-generation

The construction of new semiconductor photocatalysts toward high-efficiency splitting water has played an important role in developing sustainable and clean hydrogen energy . In this work, new type of micro/nano-sized hybrids were synthesized based on the assembly of 0D Cd 0.5 Zn 0.5 S quantum dots (QDs, size: ca. 5   nm) onto 2D graphitic carbon nitride ( g -C 3 N 4 ) ultrathin microribbons (thickness: ca. 4   nm) via an in-situ growth hydrothermal method . The Cd 0.5 Zn 0.5 S 32   wt%@C 3 N 4 composite exhibits the highest visible-light-driven H 2 -generation rate of 33.41   mmol   h −1   g −1 without any noble-metal as cocatalyst , and the apparent quantum efficiency is 46.65% at 450   nm. Such H 2 -generation rate is higher than the pristine g -C 3 N 4 and Cd 0.5 Zn 0.5 S by a factor of 27.39 and 9.18 respectively, which is significantly enhanced compared with most as-reported noble-metal-free semiconductor catalysts to date. In addition, compared with the pristine Cd 0.5 Zn 0.5 S, the photocatalytical stability of Cd 0.5 Zn 0.5 S QDs@C 3 N 4 is highly improved. The enhanced H 2 -generation performance can be attributed to the well-matched energy level and strong electronic coupling between two components at the g- C 3 N 4 interface as well as enhanced visible-light absorption. The uniform dispersion of Cd 0.5 Zn 0.5 S QDs onto the g -C 3 N 4 ultrathin microribbons also facilitates the depression of electron-hole recombination from potential aggregation of Cd 0.5 Zn 0.5 S. Therefore, this work supplies an effective way to obtain promising 2D micro/nanostructures for high-efficiency visible light-induced H 2 -generation.