Synergistically boosted non-radical catalytic oxidation by encapsulating Fe3O4 nanocluster into hollow multi-porous carbon octahedra with emphasise on interfacial engineering

Abstract

Investigating the mechanisms of interfacial processes of supported metal catalysts is crucial for advanced oxidation processes (AOPs) of peroxymonosulfate (PMS) activation on efficient water remediation. In this research, we have successfully synthesized an exclusive nanocarbon catalyst encapsulating Fe3O4 nanoparticles in hollow multi-porous structures (termed ‘H-Fe3O4@C') as a catalyst for activating PMS towards the degradation of bisphenol-A (BPA). Superior catalytic performance of H-Fe3O4@C was observed as BPA was completely degraded within 40 min. This observation ascribed to stronger interfacial interactions between the Fe and C layer, which could be attributed to the presence of multiple Fe-C bonding that allows for electron tunnelling to the adjacent carbons than Fe3O4. The results of density functional theory calculations show that the Fe3O4 active center encapsulated in the center of the carbon framework can regulate the adsorption tenderness of carbon materials, resulting in excellent interfacial interaction provided optimal active sites with low adsorption energy(−1.31 eV) and long O-O bond(dO-O = 1.592 Å). Electrochemical analysis conceded that the atomic interfacial bonds (Fe-C) promoted electronic communication between surfaces. At the same time, the vacuum packaging structure enhances the stability of the catalyst and prevents the continuous leaching of active metals. The dissolved iron concentration after the reaction of H-Fe3O4@C was only 3.37% of that of bare Fe3O4 (14.6 mg L−1). Overall, this research sheds a new insights on the critical role of strong interfacial interactions in non-radical activation of PMS.