Fabrication of multi-scale CdS/ZnO heteroarchitectures with boosted dual photocatalytic activities for hydrogen generation and organic dye degradation under solar light

Binary multi-scale CdS/ZnO heterogeneous architectures comprised of zero-dimensional (0D) CdS nanoparticles depositing onto 3D flower-like architectures self-aggregated by 2D ZnO nanoflakes have been successfully fabricated by a facile aqueous chemical process. The H2-generation rate of the optimized CZ-3 is calculated to be 15.682 mmol g-1 h-1 under simulated solar irradiation, which is 15.25, 101.17 and 39.70 times higher than that of pristine ZnO, bare CdS, and the physical mixture, respectively. The photocatalytic oxidation kinetics rate constant over the optimal CZ-3 in degradation of Congo red is measured to be 0.05686 min-1 under simulated sunlight, which reaches 7.21, 9.07, 5.82 folds higher than that of pristine ZnO, pure CdS, and the physical mixture, respectively. The dual boosted photocatalytic performance of CdS/ZnO composite is assigned to the synergetic multi-scale heteroarchitecture with the interfacial heterojunction. The photocatalytic electron transfer mechanism is proposed based on the perfect band matching and the free radical experiments.