Fully integrated Ag nanoparticles/ZnO nanorods/graphene heterostructured photocatalysts for efficient conversion of solar to chemical energy

We demonstrate the synthesis of heterostructured photocatalysts that comprise high-density unaggregated plasmonic Ag nanoparticles (AgNPs) chemically bound to vertically aligned ZnO nanorod arrays (ZNRs) that were grown on graphene (GR)-containing solid substrates to form ordered heterostructures without agglomeration. The photocatalysts provide the capability to monolithically integrate the photocatalytic functionality of AgNPs, ZNRs, and GR, which significantly enhances solar light absorption, suppresses charge recombination, and provides an ultrahigh density of catalytic reaction centers. Surprisingly, the AgNPs ZNRs GR heterostructures exhibit a photocatalytic reaction rate 13.8 times higher than that recorded for the bare ZNRs under solar light illumination. As depicted by geometric characterization, ultraviolet photoelectron spectroscopy, photoluminescence spectroscopy, and electromagnetic field simulation, the extraordinary photocatalytic performance could be attributed to the synergetic effect of electronic and plasmonic coupling, as well as the unique geometry. (C) 2015 Elsevier Inc. All rights reserved.