Perfect inhibition of CdS photocorrosion by graphene sheltering engineering on TiO2 nanotube array for highly stable photocatalytic activity

Phys Chem Chem Phys. 2014 Dec 14;16(46):25321-9. doi: 10.1039/c4cp04057k. Epub 2014 Oct 22.

Abstract

An artful graphene sheltering engineering onto TiO2 nanotube array for perfect inhibition of CdS photocorrosion (RGO/CdS-TiO2 NT) has been developed by a one-step electrodeposition method. The CdS photocorrosion driven by both holes and radicals has been systematically investigated and identified. The RGO layer provides a perfect protection to CdS through (i) blocking the attack of active species especially ˙OH radicals and (ii) offering a closed electron-rich microenvironment where the stored electrons RGO(e(-)) not only reduce intermediate species S˙(-) to S(2-) but also compensate the valence band of CdS for its loss of electrons to alleviate CdS photocorrosion from oxidation by holes. The photocatalyst exhibits extremely high stability. RGO/CdS-TiO2 NT shows high visible-light photocatalytic activity for the degradations of organic dye methylene blue (MB), industrial chemical p-nitrophenol (PNP) and herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). This work provides a new insight into the protection of photosensitive semiconductors from photocorrosion.