Metal–organic framework-derived magnetic carbon for efficient decontamination of organic pollutants via periodate activation: Surface atomic structure and mechanistic considerations

Abstract

Practical implementation of periodate-based advanced oxidation processes for environmental remediation largely relies on the development of cost-effective and high-performance activators. Surface atomic engineering toward these activators is desirable but it remains challenging to realize improved activation properties. Here, a surface atomic engineering strategy used to obtain a novel hybrid activator, namely cobalt-coordinated nitrogen-doped graphitic carbon nanosheet-enwrapped cobalt nanoparticles (denoted as Co@NC-rGO), from a sandwich-architectured metal–organic framework/graphene oxide composite is reported. This activator exhibits prominent periodate activation properties toward pollutant degradation, surpassing previously reported transition-metal-based activators. Importantly, the activator shows good stability, magnetic reusability, and the potential for application in a complex water matrix. Density functional theory modeling implies that the strong activation capability of Co@NC-rGO is related to its surface atomic structure for which the embedded cobalt nanoparticles with abundant interfacial Co–N coordinations display modified electronic configurations on the active centers and benefit periodate adsorption. Quenching experiments and electrochemical measurements showed that the system could oxidize organics through a dominant nonradical pathway. Additionally, a lower concentration of cobalt leaching was observed for the Co@NC-rGO/periodate system than for its Co@NC-rGO/persulfate counterpart. Our work provides a pathway toward engineering surface atomic structures in hybrid activators for efficient periodate activation.