Co/Fe co-doped porous graphite carbon derived from metal organic framework for microelectrolysis-Fenton catalytic degradation of Rhodamine B

Abstract

Co/Fe co-doped porous graphite carbon (Co/Fe-PGC) nanocomposites were successfully prepared by one-step pyrolysis with CoFe-MOF, in which the Co/Fe nanoparticles were uniformly coated on porous graphite carbon derived from MOF. It was used to microelectrolysis-Fenton degrade rhodamine B through the main active substance ∙OH. The color and TOC removal rate of 100 mg/L rhodamine B reached 99.41% and 64.6%, respectively, for 30 min. Rhodamine B was degraded into small molecular organic acids, alcohols and lipids by N-demethylation and chromophore cleavage, until it was finally degraded into CO2 and H2O, and no new colored organics were produced in the degradation process. The degradation process follows the first-order reaction kinetics, and its rate constant is much higher than that of the previous similar studies. The excellent catalytic performance of Co/Fe-PGC catalyst is attributed to the coupling effect of micro-electrolysis and Fenton reaction, and the acceleration of cobalt on electron transport and Fe2+ reduction. Co0/Fe0 undergoes galvanic corrosion to generate Co2+/Fe2+ and H2O2, and then these products undergo Fenton reaction to generate Co3+/Fe3+ and ∙OH, thus forming a circulating system of Co3+/Fe3+ and Co2+/Fe2+, enhancing the activation of H2O2 and ensuring the efficient degradation of RhB.