High-efficiency photoelectrocatalytic hydrogen generation enabled by Ag deposited and Ce doped TiO2 nanotube arrays

摘要

Visible light driven anatase Ag-Ce/TiO2 NTs was prepared by doping rare earth element Ce and decorating noble metal Ag nanoparticles to exhibit highly efficient photocatalytic performance. Ce doped TiO2 nanotube arrays (Ce/TiO2 NTs) were successfully fabricated by the electrochemical anodic oxidation of pure titanium in an NH4F electrolyte solution containing cerium ions. Then Ag nanoparticles (Ag NPs) were assembled in Ce/TiO2 NTs by microwave-assisted chemical reduction (Ag-Ce/TiO2 NTs). Samples were characterized by different techniques such as, X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence spectrum (PL), UV-vis absorption spectrum (UV-vis), and Raman spectrum. The UV-vis diffusion reflectance spectrum (UV-vis) and photoluminescence spectrum (PL) indicated that Ag deposited and Ce doped TiO2 showed higher visible light absorption activity and lower electron hole pair recombination rate. The results showed that Ce ions were incorporated into the lattice of TiO2, which can broaden the absorption region to visible light, and inhibit the recombination of the photo-generated electron and hole pairs. Furthermore, Ag NPs were well dispersed on the surface of Ce/TiO2 NTs with metallic state, which can enhance the visible absorption of TiO2 NTs based on the local surface plasmon resonance effect (LSPR) of Ag NPs. In addition, the photocatalytic activity of Ag Ce/TiO2 NTs was largely enhanced by using 0.2 mM Ag-0.3 mM Ce/TiO2 NTs as catalyst. Finally, the mechanism of H-2 production by water splitting under both UV and visible light irradiation was also proposed. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.