Electrothermal regeneration by Joule heat effect on carbon cloth based MnO2 catalyst for long-term formaldehyde removal

Carbon-based materials (e.g., activated carbon) have been widely used as contaminant removal media due to their unique adsorption properties. However, some of their other characteristics, such as electrothermal properties, have been greatly ignored in the field of environmental remediation. Herein, a kind of carbon cloth (CC)-supported MnO2 composite (MnO2-CC) was prepared and investigated for catalytic oxidation of gaseous formaldehyde (HCHO) under the assistance of electric power. The MnO2-CC composite exhibited unique Joule heat property and could efficiently convert electrical energy into heat energy. The surface temperature of MnO2-CC composite could be increased to as high as 138 °C within 20 s when 8 V input voltage was imposed. In addition, porous MnO2 nanosheets dispersed uniformly on the surface of CC surface, forming a kind of hierarchical core-shell structure. The close contacted interface could reduce energy loss during heat transfer. As a result, the used MnO2-CC composite could exhibit long-term HCHO removal efficiency by highly effective electrothermal regeneration. This work represents a convenient and fast approach that allows direct utilization of electric power to accelerate the complete mineralization of HCHO. The in-situ fast electric heating process along with the uniform dispersion of porous MnO2 on CC make the MnO2-CC fabric an excellent material for indoor HCHO abatement.