Coupling N-doping and confined Co3O4 on carbon nanotubes by polydopamine coating strategy for pleiotropic water purification

The development of effective and sustainable solutions for pleiotropic water purification becomes urgent and attractive. Heterogeneous Fenton-like catalysts for activation of peroxymonosulfate (PMS) to purify organic wastewater show great promise. In this work, by tuning metal loading with an in-situ polydopamine coating strategy, oxygen vacancy-enriched Co3O4 loading on N-doped carbon nanotubes (CNTs) were constructed to enhance PMS activation efficiency for pollutants degradation. Impressively, the obtained modified CNTs afford a well-developed N-containing network structure, which is further endowed with abundant Co(II)/Co(III) redox cycles and significant metal-carbon interactions. In particular, the surface N doping in CNTs might induce the oriented enrichment of pollutants around the catalyst, which reduces the migration distance and correspondingly improves the utilization of reactive oxidative species. The electron transfer efficiency of the catalyst can be further improved by incorporating oxygen vacancy-enriched Co3O4. The performance results show that the optimal NC/Co-1 could mineralize 20 x 10-6 of bisphenol A (BPA) by almost 98% in 8 min. A low reaction activation energy (26.05 kJ center dot mol(-1)) in BPA degradation was demonstrated by the NC/Co-1. More importantly, NC/Co-1 can inherit excellent degradation performance towards oxytetracycline, 2, 4-dichlorophenol, and tetracycline, showing wide practical flexibility. In addition, by virtue of the photothermal conversion property, NC/Co-1 achieves an additive function for interfacial solar water evaporation (1.84 kg center dot m(-2)center dot h(-1), 112.51%), showing impressive potential for clean water recovery under complicated environmental pollution conditions.