Tip-grafted Ag-ZnO nanorod arrays decorated with Au clusters for enhanced photocatalysis

The design and optimization of semiconductor-metal/metal cluster heterostructures are highly desirable for efficient photocatalytic redox reactions. Herein, Ag-tipped ZnO nanorod arrays decorated with glutathione-protected Au clusters (ZnO-Ag-Au NRAs) have been successfully prepared via photodeposition method and electrostatic self-assembly method, in which Ag nanoparticles are demonstrated to act as an electron mediator and Au clusters serve as a visible light photosensitizer to generate additional charge carriers in the composite photocatalyst. With selective tip growth of metallic Ag and surface decoration of Au clusters on ZnO NRAs, the as-obtained ZnO-Ag-Au NRAs operate to boost the charge separation and transfer, thereby showing the enhanced photocatalytic reduction of aqueous heavy metal ions. This work affords a feasible paradigm for the fine construction of tipped one-dimensional-based hybrid photocatalysts with enhanced activity toward the elimination of heavy metal pollutants from aqueous solutions.