Enhanced photocatalytic performance of Au/TiO_2 nanofibers by precisely manipulating the dosage of uniform-sized Au nanoparticles

摘要

The drawback of using TiO_2 in photocatalytic applications lies in the wide band gap and high recombination rate of charge carriers. To solve the above problems, modification of TiO_2 with Au nanoparticles (NPs) has received considerable attention. Here, TiO_2 nanofibers uniformly deposited with Au NPs which have a narrow size distribution (16 nm) were synthesized. We demonstrate that the photocatalytic performance of Au/TiO_2 heterostructured nanofibers can be effectively enhanced under UV and visible light irradiation by manipulating the dosage of decorated Au NPs. The effect of metal dosage on the photocatalytic performance has been systematically investigated. The enhanced photocatalytic properties are ascribed to the increase of visible light absorption from the Au NP's surface and the enhancement of separation of electron-hole charge pairs at the interface of Au/TiO_2 junctions. Besides, the decrease of photoactivity with more addition of Au NPs is due to the fact that redundant Au NPs reduce the photon flux reaching the TiO_2 surface and also act as recombination centers for electron-hole pairs. The present work provides guidance toward the fabrication of more efficient Au/TiO_2 photocatalysts.