Construction of MIL-53(Fe) metal-organic framework modified by silver phosphate nanoparticles as a novel Z-scheme photocatalyst: Visible-light photocatalytic performance and mechanism investigation

By Liangcheng Xie, Zhao-hui Yang, Weiping Xiong, Yaoyu Zhou, Jiao Cao, Yanrong Peng, Xin Li, Chengyun Zhou, Rui Xu, Yanru Zhang. Applications of Surface Science, 2019

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Abstract Novel heterostructure photocatalysts consisted of MIL-53(Fe) and silver phosphate (Ag3PO4) were successfully developed through a simple in situ precipitation strategy in this work. The photocatalytic activities of the as-synthesized samples were assessed via multiple antibiotics degradation, including tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC) and deoxytetracycline (DCL). All the obtained Ag3PO4/MIL-53(Fe) composites exhibited much more superior photocatalytic activities than pure MIL-53(Fe) and Ag3PO4. Especially, the optimal composite with 1:3 mass ratio of Ag3PO4:MIL-53(Fe) (APM-3) displayed the best photocatalytic activity, for which the removal of antibiotics was 93.72% (TC), 90.12% (OTC), 85.54% (CTC) and 91.74% (DCL) under visible light irradiation for 1 h. The APM-3 also exhibited good photostability and recyclability. Three-dimensional (3D) EEMs (excitation-emission matrix fluorescence spectroscopy) was applied to further investigate the TC degradation process, and the TC intermediates were identified by high-performance liquid-mass spectrometry (HPLC-MS). The possible degradation pathway for TC was also discussed. In addition, electron spin resonance (ESR) measurement and quenching experiments verified that O2−, OH and h+ radicals all worked during the degradation process. In the end, a possible Z-scheme heterostructure model composed of MIL-53(Fe), metallic Ag and Ag3PO4 was proposed, in which the small reducible Ag nanoparticles functioned as a center for charge transmission. Powerful redox ability and effective separation of photoinduced carriers can be achieved in this Z-scheme heterostructure system. The findings of this work could offer a novel way to design MOF-based materials for remediation of contaminated water.

Subfields: Inorganic Chemistry, Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/6747e831bc1ae541125ce649ebbaf11d2ecbcfed