Three-dimensional plasmonic photoanode of Au nanoparticles/ZnFe2O4 nanosheets coated onto ZnO nanotube arrays for photoelectrochemical production of hydrogen

Abstract

The application of single-phase ZnO in hydrogen production through photoelectrochemical (PEC) water reduction is limited because of its unability to utilize photon energy of visible light and high carrier recombination rate. Herein, a three-dimensional (3D) plasmonic photoanode consisting of Au nanoparticles/ZnFe2O4 nanosheets coated onto ZnO nanotube arrays (Au/ZnFe2O4/ZnO NTAs) is rationally designed for hydrogen generation via PEC water splitting. The measurements preformed under simulated solar light and visible light irradiation show that the hot-electron injection of Au nanoparticles (NPs) significantly enhances PEC water splitting for hydrogen generation of 3D plasmonic Au/ZnFe2O4/ZnO NTAs photoanode. Benefiting from the outstanding visible light harvesting ability of ZnFe2O4 nanosheets, efficient suppression of carrier recombination by a favorable band alignment, hot-electron injection of Au NPs and large surface area of 3D architecture, the 3D plasmonic Au/ZnFe2O4/ZnO NTAs photoanode exhibits enhanced PEC water splitting for hydrogen generation. The hydrogen generation rate obtained by 3D plasmonic Au/ZnFe2O4/ZnO NTAs photoanode is 1.5 and 5.7-fold of ZnO/ZnFe2O and ZnO NTAs photoanodes, respectively, at 0.6 V versus reference electrode (Ag/AgCl) under simulated solar light irradiation.