Pure　Zinc　Oxide　(ZnO)　nanoparticles　(NPs)　and　gold　(Au)　decorated　(Au-ZnO)　hetero-nanostructures　were　synthesized　using　green-synthesis　method　employing　pecan　nuts　(Carya　illinoinensis)　leaves　extract　as　reducing　agent.　The　structural　and　optical　properties　studied　by　X-ray　diffraction　(XRD),　Fourier　transform　infrared　spectroscopy　(FTIR),　Scanning　electron　microscopy　(SEM),　Energy-dispersive　X-ray　spectroscopy　(EDX),　High-resolution　transmission　electron　microscopy　(HRTEM)　and　UV-vis　spectrophotometer　(UV-vis).　Structural　modification　with　the　introduction　of　Au　in　ZnO　have　been　confirmed　by　the　XRD　and　TEM　results.　UV　data　confirmed　the　decrease　in　Au-ZnO　energy　band-gap　E-g　value,　which　validates　the　formation　of　hetero-structure.　The　modulation　of　energy　band-gap　causes　visible　light　absorption　and　hence　enhances　the　photodegradation　activity　of　Au-ZnO.　Photocatalytic　activity　was　carried-out　by　degradation　of　RhB　dye　under　UV　light　irradiation　in　aqueous　solution.　The　maximum　degradation　of　95　%　was　obtained　during　the　time　of　180　min　for　the　basic　pH　of　the　dye.　The　Enhanced　degradation　in　Au-ZnO　as　compared　with　bare　ZnO　NPs,　was　attributed　to　Au,　which　controls　the　amount　of　electron　and　suppress　electron-hole　ratio　at　ZnO　surface.　In　the　recycling　study　of　the　Au-ZnO　Photocatalyst,　the　hetero-structure　showed　good　stability　up　to　five　cycles.