Fabrication of PbS quantum dots decorated ZnO nanorod arrays on Zn substrate and their visible light photocatalytic application

• Seed-free hydrothermal synthesis of highly oriented ZnO nanorod arrays on Zn foil.
• PbS QDs evenly cover the surface of ZnO nanorods via SILAR method.
• Highly dense ZnO nanorods well protect zinc foil from destroying by Lead nitrate.
• PbS-sensitized ZnO nanorod thin films exhibit high sunlight catalytic activity.

PbS quantum dots(QDs)-decorated ZnO nanorods grown on zinc foil were successfully fabricated via the successive ionic layer adsorption and reaction (SILAR) method. The high-density ZnO nanorods were first synthesized in a seed-free n-butylamine hydrothermal system only adding lanthanum nitrate as nucleating agent. Then, PbS QDs, with a cubic rock-salt structure and little composition derivation from the stoichiometry, evenly deposited on the surface of ZnO nanorods with no damage of zinc foil. The as-obtained PbS-sensitized ZnO nanorod films exhibited the full spectrum of sunlight absorption and outstanding photocatalytic activity for the degradation of methyl orange under sunlight irradiation. The SILAR cycles significantly effected the grain size and thickness of PbS nanocrystalline layer and even its photocatalytic activity. This is the first study to ever report using PbS nanoparticles to decorate Zn-based ZnO nanorod via SILAR method, which allows manufacturing high quality QDs-sensitized ZnO photocatalyst and gas sensor on low-cost Zn substrate.