Fabrication and Application of Magnetically Catalytic Imprinting Nanozymes

Nanozymes exhibit excellent enzyme‐like activities but lack specificity. Here, molecularly imprinted polymers (MIPs) based on polypyrrole (PPy) and using methylene blue (MB) as template were grown on Fe 3 O 4 nanozymes to enhance the catalytic selectivity. The obtained composite Fe 3 O 4 @PPy MIPs were characterized using a scanning electron microscope, transmission electron microscope, powder X‐ray diffractometer, and vibrating sample magnetometer. The PPy‐encapsulated Fe 3 O 4 nanozymes retained their catalytic ability and almost completely removed MB within 30 min in the presence of sodium persulfate. In comparison with bare Fe 3 O 4 nanozymes, the Fe 3 O 4 @PPy MIPs showed superior catalytic selectivity for MB. The apparent rate constants ( k app ) for MB, rhodamine B, and methyl orange were 0.073, 0.035, and 0.012 min −1 , respectively. Even after five recycling steps, the obtained Fe 3 O 4 @PPy MIPs could degrade more than 80% of MB.