Yolk@shell nanoreactor for heterogeneous Fenton reaction: A review of recent progress

Heterogeneous Fenton reaction was a promising technology to non-selectively degrade organic pollutants, providing a feasible solution to environment problems. The essential issue in Fenton reaction was the high efficient catalyst design, and the yolk@shell structure was usually functioned as the nanoreactor to boost activation efficiencies of H2O2 (or peroxymonosulfate (PMS)). In typical, a yolk@shell nanoreactor was constructed from a hollow shell and a movable core, which could transfer Fenton reaction performed in the bulk solution to the internal cavity. Benefiting from the confinement effect, the collision opportunity among various reactants was increased, the degradation rate was accelerated, the H2O2 (or PMS) utilization efficiency was boosted, the environmental tolerance of catalysts was improved, and the metal leaching was lowered. Therefore, yolk@shell nanoreactor provided an ideal platform for heterogeneous Fenton reaction. In addition, many methods could be adopted to tailor the yolk@shell nanoreactor for better catalytic performance, and this inspired researchers to design nanoreactor with optimized compositions and novel structures. At present, many reviews on either preparation and application of yolk@shell nanoreactor or recent development of heterogeneous Fenton reaction were reported, however, the strategies to improve the Fenton reaction based on yolk@shell nanoreactor have not been detailed discussed. This review have illustrated the recent progress on yolk@shell nanoreactor for heterogeneous Fenton reaction, and provided an comprehensive information on catalyst design, catalytic performance, catalytic mechanism, catalyst advantage, catalyst improvement method, aiming at catalyst with better performance.