MOF etching-induced Co-doped hollow carbon nitride catalyst for efficient removal of antibiotic contaminants by enhanced perxymonosulfate activation

The low surface area, low porosity, weak charge transport, and metal species loss of conventional metal-based carbon materials are the main defects limiting their environmental application. In this study, a metal–organic framework (MOF)-supported Co-doped hollow carbon nitride (ZCCN) catalyst was constructed by etching zeolitic imidazolate framework-67 (ZIF-67). Excellent visible light capture and electron transfer performance of the catalyst were revealed, and 99% tetracycline (TC) degradation and 65.9% peroxymonosulfate (PMS) decomposition were achieved within 40 min. Efficient separation and transport of photogenerated electrons are the key to PMS activation and TC degradation. Meanwhile, the preserved skeleton structure of ZIF-67 and the triazine rings of carbon nitride endowed the catalyst with enhanced stability and lessened Co leaching. Density functional theory (DFT) was applied to investigate the internal effect of PMS activation on Co sites. The reduced toxicity of the intermediates revealed the potential of the ZCCN/PMS system on eliminating environmental risks caused by TC. This study provides new insights into the design of stable MOF-derived metal-based heterogeneous catalysts.