期刊
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
卷 91, 期 -, 页码 17-27出版社
JOURNAL MATER SCI TECHNOL
DOI: 10.1016/j.jmst.2021.02.051
关键词
Graphene oxide; Chromium (VI); Defect density; UV-irradiation modification; Photocatalytic reduction
资金
- National Natural Science Foundation of China [21876003, 41961134034]
- Second Tibetan Plateau Scientific Expedition and Research [2019QZKK0607]
- 111 Project Urban Air Pollution and Health Effects [B20009]
This study explores the use of UV-modified rGO as a sole photocatalyst for efficient removal of Cr(VI) under visible light. UV irradiation leads to reduction of oxygen-containing functional groups on GO surface, enhancing the photocatalytic activity of rGO.
Graphene oxide (GO), a new and promising material, has been widely used as a co-catalyst in photocatalytic reactions; however, its capacity as a sole photocatalyst has rarely been investigated. In this study, ultraviolet (UV) light irradiation was used as a modification method to obtain reduced GO (rGO) samples. The samples were used as photocatalysts to examine their visible light photocatalytic activity toward hexavalent chromium (Cr(VI)) removal. Atomic force microscopy (AFM), X-ray diffraction (XRD), UV-vis spectrophotometry, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron spin resonance (ESR) spectroscopy were applied to interpret the surface and structure changes with UV irradiation. The oxygen-containing functional groups (OFGs) on the GO surface were reduced to defective carbons and pi-conjugated C=C (sp(2) domains) under UV light; this led to a decrease in the interlayer distance between GO sheets, GO fragmentation, and increased disorder on the GO surface. The restoration of sp(2) domains led to a narrower band gap of GO, which favored the rGO excitation by visible light to generate electron-hole pairs. The rGO pre-irradiated with UV for 1h (rGO-1), possessing the highest defect density and electron generation efficiency, exhibited the best Cr(VI) reduction efficiency, which was about three times that of the GO sample; moreover, it outperformed most of the reported GO-based nanomaterials. In addition, low pH and the addition of citric acid as a hole scavenger could further improve the photocatalytic activity. This study proves that GO or rGO can be used as a sole photocatalyst under visible light to remove environmental pollutants such as heavy-metal ions, and it paves the way for the development of this kind of material and its UV-irradiation modification for further applications. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据