Catalytic Pollutant Upgrading to Dual‐Asymmetric MnO ₂@polymer Nanotubes as Self‐Propelled and Controlled Micromotors for H ₂O ₂ Decomposition

Abstract

Industrial and disinfection wastewater typically contains high levels of organic pollutants and residue hydrogen peroxide, which have caused environmental concerns. In this work, dual‐asymmetric MnO ₂@polymer microreactors are synthesized via pollutant polymerization for self‐driven and controlled H ₂O ₂ decomposition. A hollow and asymmetric MnO ₂ nanotube is derived from MnO ₂ nanorods by selective acid etching and then coated by a polymeric layer from an aqueous phenolic pollutant via catalytic peroxymonosulfate (PMS)‐induced polymerization. The evolution of particle‐like polymers is controlled by solution pH, molar ratios of PMS/phenol, and reaction duration. The polymer‐covered MnO ₂ tubing‐structured micromotors presented a controlled motion velocity, due to the reverse torque driven by the O ₂ bubbles from H ₂O ₂ decomposition in the inner tunnels. In addition, the partially coated polymeric layer can regulate the exposure and population of Mn active sites to control the H ₂O ₂ decomposition rate, thus avoiding violent motions and massive heat caused by vigorous H ₂O ₂ decomposition. The microreactors can maintain the function of mobility in an ultra‐low H ₂O ₂ environment (<0.31 wt.%). This work provides a new strategy for the transformation of micropollutants to functional polymer‐based microreactors for safe and controlled hydrogen peroxide decomposition for environmental remediation.