A simple and green method to prepare non-typical yolk/shell nanoreactor with dual-shells and multiple-cores: Enhanced catalytic activity and stability in Fenton-like reaction.

Nowadays, non-typical yolk/shell structure has drawn much attentions due to the better catalytic performance than traditional counterparts (one yolk/one shell). In this study, ZIF-67 @CoSiO/SiO yolk/shell structure was prepared in one-step at room temperature, in which ZIF-67 was served as the hard-template, HO was served as etchant and tetraethyl orthosilicat was served as the raw material for CoSiO/SiO. After calcination, the non-typical CoO @CoSiO/SiO yolk/shell nanoreactor with CoSiO/SiO dual-shells and CoO multiple-cores was obtained. On the one hand, more active sites were exposed on multiple-cores surface and better protection were provided by dual-shells. On the other hand, the sheet-like CoSiO inner shell not only extended the travel path and retention time of pollutants trapped in cavity, but also separated the multiple-cores from aggregation. Therefore, the nanoreactor displayed the outstanding catalytic activity and recyclability in Fenton-like reaction. Metronidazole (20 mg/L) was completely degraded after 30 min, rhodamine B (50 mg/L) and methyl orange (20 mg/L) were removed even within 5.0 min. Catalytic mechanism indicated that O greatly contributed to the pollutant degradation. This paper presented a simple, versatile, green and energy-saving method for non-typical yolk/shell nanoreactor, and it could inspire to prepare other catalysts with high activity and stability for environmental remediation.