High-Performance Coral Reef-like Carbon Nitrides: Synthesis and Application in Photocatalysis and Heavy Metal Ion Adsorption

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• 作者：Jeannie Z. Y. Tan ; Natalita M. Nursam ; Fang Xia ; Marc-Antoine Sani ; Wei LiXingdong Wang ; Rachel A. Caruso
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：9
• 期：5
• 页码：4540-4547
• 全文大小：482K
• ISSN：1944-8252

文摘

Synthesis of carbon nitrides (CN_x) by refluxing under nitrogen exhibited mixed growth mechanisms of oriented attachment and Ostwald ripening, leading to the formation of coral reef-like microstructures from spherical agglomerates. Some phase transformation from β-phase to α-phase CN_x occurred upon refluxing for 1.5 h, producing a biphasic CN_x. The N content relative to C was determined from CHN elemental analysis, and the presence of C═N and terminal groups (i.e., COOH and NH₂) was consistent with the Fourier transform infrared, nuclear magnetic resonance, and X-ray photoelectron spectroscopic results. The sample refluxed for 2.0 h (CN_x/2.0 h) had the highest surface area of 24.5 m²·g^–1 and displayed enhanced adsorption capacities for methylene blue (MB) molecules and heavy metal ions Pb²⁺ (720 mg·g^–1), Cd²⁺ (480 mg·g^–1), and As(V) (220 mg·g^–1), which was attributed to the presence of COOH functional groups. CN_x samples had a negative surface charge that electrostatically attracted the cationic heavy metal ions as well as MB molecules for subsequent photodecomposition under visible-light illumination. The photocatalytic activity of CN_x/2.0 h toward phenol, a common pollutant in aqueous waste, was also demonstrated and a possible photocatalytic route was proposed.