Confinement of ZIF-derived copper-cobalt-zinc oxides in carbon framework for degradation of organic pollutants

Abstract

Developing efficient heterogeneous catalysts for peroxymonosulfate (PMS) activation is extraordinarily desirable in water purification. In this work, a well-defined core-shell copper-cobalt-zinc oxides consisting of Cu0.92Co2.08O4 and ZnCo2O4 wrapped by carbon (CuCoZnO/C) was fabricated by a simple one-step calcination using metal-organic frameworks (MOFs) as templates. The as-obtained catalysts were fully characterized and utilized to activate PMS for phenol degradation, and almost 100% degradation efficiency could be achieved within 10 min. The distinct hollow structure allowed the high instantaneous concentration of organic pollutant in a microenvironment, thus providing a driving force to improve the reaction rate. Owing to the mesoporous and adsorptive carbon as well as active Cu0.92Co2.08O4 shell, most SO4•− radical was confined to catalyst surface immediately once produced rather than release into the bulk solution, making the enriched reactant molecules contact active sites more easily. Further investigation found that both surface-bound SO4•− and 1O2 were dominantly participated in the catalytic process, achieving an ultrafast pollutant degradation. This work offered a new design for multiple complex oxides from MOFs and extended the development of Co-based heterogenous catalyst in PMS activation for the environmental remediation.