Graphitic Carbon Nitride with Superior Visible Light Absorption Using Alkali Metal Halide Eutectic Salt
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초록
내용
Graphitic carbon nitride(g-CN) has been considered a promising visible light photocatalyst. Despite great chemical/thermal stability and unique electronic properties, pristine g-CN has poor photocatalytic activity under visible light because of limited absorption of visible light and fast charge recombination induced by high density of defects. To overcome these intrinsic problems, we propose a simple method to improve visible light activity of g-CN. Ionothermal approach is employed using eutectic mixtures of LiI:KI and LiBr:KBr. Detailed analyses by XRD, FT-IR, 13C CP-MAS NMR, XPS, UV-Vis spectroscopy, PL spectroscopy indicate that both triazine and heptazine phases are simultaneously formed. Furthermore, cyano group, which induces localization of electrons on g-CN, is also introduced with LiI:KI system without critical structural collapse. These characteristics significantly improve visible light absorption, charge separation and transfer, photocatalytic activity under visible light.