Enhanced the synergistic degradation effect between active hydroxyl and reactive oxygen species for indoor formaldehyde based on platinum atoms modified MnOOH/MnO2 catalyst

Abstract

Maintaining high activity during prolonged catalysis is always the pursuit in catalytic degradation of organic pollutants. For indoor formaldehyde (HCHO) degradation, the accumulation of intermediates is the major factor limiting the conversion of HCHO to final product CO2 (HCHO-to-CO2 conversion) and long-lasting catalysis. Herein, a three-dimensional radialized nanostructure catalyst self-assembled by MnOOH/MnO2 nanosheets anchored with Pt single atoms (PtSA-MnOOH/MnO2 with a trace platinum loading amount of 0.09%) is developed by thermally assisted two-step electrochemical method, which achieves enhanced CO2 production in catalytic HCHO degradation at the room temperature by the collaborative action of active hydroxyl (OH*) and active oxygen species (O2*). By boosting intermediates’ decomposing, the catalyst implements real-time HCHO-to-CO2 conversion (∼85.7%) and long-term continuous HCHO removal (∼98%) during 100 h in a 15 ppm HCHO atmosphere at 25 °C under a weight hourly space velocity of 30000 mL/gcat∙h. Density functional theory calculation shows that the formation energy of O2* from O2 over PtSA-MnOOH/MnO2 is nearly half lower than that over Pt-MnO2 catalyst. And decomposing accumulated intermediates gives the credit to OH* species sustainably generated by the combined action of MnOOH and O2*. The synergistic action between PtSA and MnOOH contributes to the continuous production of O2* and OH* for enhancing CO2 production in indoor catalytic formaldehyde degradation.