Room temperature Zinc-metallation of cationic porphyrin at graphene surface and enhanced photoelectrocatalytic activity

Publication date: 15 March 2018
Source:Applied Surface Science, Volume 434
Author(s): Rongjin Zeng, Guoliang Chen, Chungang Xiong, Gengxian Li, Yinzhi Zheng, Jian Chen, Yunfei Long, Shu Chen
A stable zincporphyrin functionalized graphene nanocomposite was prepared by using positively charged cationic porphyrin (5,10,15,20-tetra(4-propyl pyridinio) porphyrin, TPPyP) and successive reduced graphene oxide (rGO) with tuned negative charge. The nanocomposite preparation was accompanied first by distinct electrostatic interactions and π-π stacking between TPPyP and rGO, and followed by fast Zinc-metallation at room temperature. In contrast to free TPPyP with Zn²⁺, the incorporation reaction is very slow at room temperature and heating or reflux conditions are required to increase the metallation rate. While at the surface of rGO nanosheet, the Zinc-metallation of TPPyP was greatly accelerated to 30min at 25°C in aqueous solution. The interaction process and composites formation were fully revealed by significant variations in UV–vis absorption spectra, X-ray photoelectron spectra (XPS) measurements, atomic force microscope (AFM) images, and fluorescence spectra. Furthermore, photoelectrochemical activity of resultant rGO/TPPyP-Zn nanocomposites was evaluated under visible-light irradiation, and enhancement of the photoelectrocatalytic reduction of CO2 was achieved.

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