Maximally exploiting active sites on Yolk@shell nanoreactor: Nearly 100% PMS activation efficiency and outstanding performance over full pH range in Fenton-like reaction

In Fenton-like reaction, peroxymonosulfate (PMS) could be activated by either transition metals or graphitized carbon. These two activation paths had their own advantages and disadvantages. To simultaneously increase the PMS activation efficiency and degradation performance, lower the metal leaching, and improve the environmental adaption; herein, a yolk@shell nanoreactor was designed, where Kirkendall effect induced abundant hollow CoO nanoparticles were encapsulated inside a Co, N atoms co-doped graphitized carbon (Co-N-GC) shell. Because of the full exploitation of active sites on yolk@shell nanoreactor, nearly 100% of PMS activation efficiency was realized and 80.0% of tetracycline (TC) (50 mg/L) was degraded within 40 min. Under the protection of Co-N-GC shell, TC were effectively degraded over the full pH range or in the presence of various inorganic anions, and the leached Co2+ was only 0.462 mg/L even after 5 cycles. This study provided a new vision to improve the Fenton-like reaction using yolk@shell nanoreactor.