Precursor design in a self-templating strategy for carbon-encapsulated bimetallic CoFe catalysts: Boosting organic pollutant degradation via nonradical pathways

Abstract

Designing high-performance heterostructure catalysts for peroxymonosulfate (PMS) activation is a promising research area. PMS-driven organic pollutant degradation via radical pathways usually suffers from the interference of other coexisting matters. In this study, we took a source design approach and employed a self-templating strategy using Prussian blue analog (PBA) precursors to fabricate CoFe/C heterostructure catalysts dominated by a nonradical pathway. Slow-speed coordination renders the CoFe PBA precursor with a highly ordered crystal structure and fewer coordinated water, resulting in an ideal carbon-encapsulated CoFe bimetallic catalyst (CoFe-S-T) with more high-valence metals and a graphitized carbon layer in its heterostructure; the obtained catalyst is proven to have superior catalytic performance for tetracycline (TC) degradation through a nonradical pathway in PMS-driven oxidation. The high CoIII/CoII ratio and surface oxygen content make CoFe-S-T an excellent catalyst by boosting the generation of 1O2, which is the predominant active species. In addition, CoFe-S-T has a high proportion of graphitized carbon layers, which significantly improves the direct electron transfer pathway. Thus, utilizing precursor design in a self-templating strategy is an effective method to synthesize high-performance heterostructures for PMS-driven organic pollutant degradation.