High-Efficiency Plasmon-Enhanced and Graphene-Supported Semiconductor/Metal Core-Satellite Hetero-Nanocrystal Photocatalysts for Visible-Light Dye Photodegradation and H-2 Production from Water

摘要

Solar-driven photocatalytic process based on electron-hole pair production in semiconductors is a long sought-after solution to a green and renewable energy and has attracted a renaissance of interest recently. The relatively low photocatalytic efficiency, however, is a main obstacle to their practical applications. A promising attempt to solve this problem is by combined use of metal nanoparticles, by taking advantage of strong and localized plasmonic near-field to enhance solar absorption and to increase the electron-hole pair generation rate at the surface of semiconductor. Here, we report a semiconductor/metal visible-light photocatalyst based on CdSe/CdS-Au (QD-Au) core-satellite heteronanocrystals, and assemble them on graphene nanosheets for better photocatalytic reaction. The as-synthesized photocatalyst exhibits excellent plasmon-enhanced photocatalytic activities toward both photodegradation of organic dye and visible-light H-2 generation from water. The H-2 evolution rate achieves a maximum of 3113 mu mol h(-1) g(-1) for the heteronanocrystal-graphene composites, which is about 155% enhancement compared to nonplasmonic QD-G sample and 340% enhancement compared to control QD-Au-G sample, and the apparent quantum efficiency (QE) reaches to 25.4% at wavelength of 450 nm.