科研之友
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摘要
γ-graphyne (γ-G), as a new kind of 2D carbon allotrope that consists of sp- and sp2-hybrid carbon atoms, has great potential in the development of highly efficient photocatalytic systems because of its unique properties. In this study, novel photocatalysts Ag3PO4@γ-G with excellent photocatalytic activity and photostability were successfully synthesized by a facile preparation method. The density functional theory (DFT) calculation results of Ag3PO4@γ-G composite, including the band charge density distributions, three-dimensional charge density difference and planar average electrostatic potential, indicated the successful construction of electrons transfer layer in Ag3PO4@γ-G composite. The photogenerated electrons of Ag3PO4 can be rapidly transferred to the γ-G under the driving of built-in potential well, which leads to the high separation efficiency of photogenerated carriers and greatly improves the photocatalytic performance of catalysts. The photocatalytic degradation rate of norfloxacin (NFL), 2-Hydroxynaphthalene (2-HNP) and phenol over the binary composite catalyst could reach 100% only after 8, 5 and 16 min of visible light irradiation respectively, and the apparent rate constants of which were 15.3, 9.6 and 19.7 times higher than that of the pure Ag3PO4 respectively. The analyses of LC-MS and 3D EEMs showed that the 2-HNP and NFL mainly degraded into short-chain carboxylic acids. The results of free radical quenching experiment and ESR characterization suggested that all kinds of active species worked in the degradation process, while the photogenerated holes and superoxide radicals played a dominant role. The novel addition of γ-G and the construction of electrons transfer layer in photocatalysts provide a new strategy for the design of efficient environmental remediation catalysts.
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