Isolation anchoring strategy for fabricating high-loading uniformly dispersed iron-based catalysts toward selective removal of phenolic compounds

Developing uniformly dispersed iron-based catalysts with high metal loading for selective removal of the phenolic compounds was a fundamental challenge in environmental catalysis. An isolation anchoring strategy was devised to prepare the uniformly dispersed nitrogen-doped porous carbon encapsulating iron catalyst (8-Fe@NC) with the Fe loading up to 16.33 wt%, which was attributed to a dual protective effect including anchoring effect of the 8-hydroxyquinoline (8-HQ) and isolation effect of the 8-cyclodextrin (8-CD), effectively anchoring the iron and inhibiting the agglomeration of the iron nanoparticles (NPs) during high temperature pyrolysis. As a demonstration, 8-Fe@NC achieved almost 100% 4-CP removal in 25 min and performed an excellent kobs (0.325 min(-1)). Moreover, 8-Fe@NC showed highly selective removal performance for phenolic compounds based on the hydrophobic interaction between catalysts and contaminants. The quenching experi-ments and EPR detection demonstrated that the main reactive oxygen species (ROSs) was singlet oxygen (1O2). Notably, the 8-Fe@NC/PMS system exhibited an extremely low activation energy (11.54 KJ/mol) and was even competent for pollutant removal at 0 C. This work provides a valuable insight for the design of uniformly dispersed iron-based catalysts and the activation of PMS to selectively remove phenolic compounds.