Thickness-dependent photocatalytic performance of graphite oxide for degrading organic pollutants under visible light

• Published in: Physical chemistry chemical physics : PCCP 2016-04, Vol.18 (16), p.1882-1886
• Main Authors: Oh, Junghoon, Chang, Yun Hee, Kim, Yong-Hyun, Park, Sungjin
• Format: Article
• Language: English
• Subjects: Band theory; Catalysis; Catalysts; Degradation; Environmental Pollutants - chemistry; Graphite - chemistry; Light; Light pollution; Microscopy, Electron, Transmission; Organic Chemicals - chemistry; Oxides; Oxides - chemistry; Photocatalysis; Photocatalysts; Photoelectron Spectroscopy
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c6cp00582a

Photocatalysts use sustainable solar light energy to trigger various catalytic reactions. Metal-free nanomaterials have been suggested as cost-effective and environmentally friendly photocatalysts. In this work, we propose thickness-controlled graphite oxide (GO) as a metal-free photocatalyst, which is produced by exfoliating thick GO particles via stirring and sonication. All GO samples exhibit photocatalytic activity for degrading an organic pollutant, rhodamine B under visible light, and the thickest sample shows the best catalytic performance. UV-vis-NIR diffuse reflectance absorption spectra indicate that thicker GO samples absorb more vis-NIR light than thinner ones. Density-functional theory calculations show that GO has a much smaller band gap than that of single-layer graphene oxide, and thus suggest that the largely-reduced band gap is responsible for this trend of light absorption. This study reveals that photocatalytic activity of graphite oxide materials for degrading organic pollutants under visible light depends on their thickness.