An electron transfer tuning strategy for the efficient degradation of tetracycline hydrochloride by Fe-N co-doped carbon materials activated with peroxymonosulfate

Abstract

In order to address the problems of metal leaching and low electron transfer efficiency, the iron (Fe) nitrogen (N) co-doped MOFs derived carbon catalysts presented a promising strategy to activate peroxymonosulfate (PMS) for water purification. In this work, using the MOF-5 as a template and iron phthalocyanine (FePc) and dicyandiamide (DCD) as a source, Fe, N co-doped carbons were prepared through milling and two-step pyrolysis. The catalytic performance and mechanism of the materials on tetracycline hydrochloride (TC) degradation in the PMS activation system (0.1Fe/N-CPMS) was systematically investigated. The results showed that the stable framework structure of MOFs-derived carbon conduced to encapsulate the Fe nanoparticles within the carbon skeleton, and then the xFe/N-C catalyst with hierarchical pore structure and good electrical conductivity was obtained, which significantly improved the TC catalytic performance. Notably, the 0.1Fe/N-C exhibited the greatest degradation performance achieving a degradation rate of 0.6315 min-1, which was approximately five times higher than that of N-C. Moreover, the degradation performance of the 0.1Fe/N-C kept the stability in various interference conditions, and still remained over 80% after three cycles test. Combine with the characterization and DFT calculation, the mechanism of the TC degradation in 0.1Fe/N-CPMS system was revealed by a non-radical process dominated by electron transfer, and the degradation efficiency was greatly improved by the synergistic effect of Fe/N on the as-prepared material. The received findings provide an electron transfer tuning strategy of Fe/N co-doped carbon nanomaterials synthesis for promoting the non-radical degradation pathways in the application of organic pollutants removal.