Boosting the Photothermal Oxidation of Multicomponent VOCs in Humid Conditions: Synergistic Mechanism of Mn and K in Different Oxygen Activation Pathways

Abstract

The complexity of actual industrial emissions has brought significant challenges for volatile organic compounds (VOCs) purification. Herein, Mn and K atoms were incorporated into Co₃O₄/TiO₂ through theoretical study, and its excellent properties were verified in experiments. The different pathways of oxygen activation by Mn and K were revealed by characterization experiments and theoretical calculations. Mn species effectually reduced the dissociation energy barrier of H₂O adsorbed on the surface, and the surface hydroxyl group promoted the dissociation of O₂ and the formation of ^•O₂^- under light and humid conditions. The introduction of K promoted the formation of more oxygen vacancies, which served as adsorption sites for gaseous O₂. Meanwhile, the electron transfer accelerated by K contributed to the activation of H₂O and the rapid production of ^•OH under light. The synergistic effect of Mn and K successfully achieved simultaneous improvements in the activity, stability, and water resistance of Co₃O₄/TiO₂. Furthermore, the catalyst was applied to the degradation of multicomponent VOCs, and the reaction path was analyzed through the test of intermediates, along with an investigation of the interaction among different types of VOCs. This study provided a new idea for the theoretical optimization of polymetallic catalysts and the analysis of degradation paths for multicomponent VOCs.