Engineering Ru/MnCo₃O_<i>x</i> for 1,2-Dichloroethane Benign Destruction by Strengthening C–Cl Cleavage and Chlorine Desorption: Decisive Role of H₂O and Reaction Mechanism

Abstract

Effective desorption of chlorine species is critical for hindering the formation of chlorinated intermediates in the catalytic destruction of chlorinated volatile organic compounds (CVOCs). Here, Ru/MnCo3Ox catalysts with excellent activity, reaction durability and superior chlorine transformation ability for 1,2-dichloroethane (1,2-DCE) destruction were rationally fabricated. The presence of Ru facilitates the electron transfer among Ru, Mn, Co, and O species, forming larger amounts of Ru6+/Ru4+, Mn4+, Co2+, and active oxygen species (O2–), and therefore promoting the catalytic activity via accelerating and strengthening the cleavage of the C–Cl bond at low temperatures. However, Ru species plays a neutral role in the desorption of surface chlorine species under dry conditions and the polychlorinated byproducts such as CH2Cl2, CHCl3, CCl4, CH2ClCHCl2, and CHClCCl2 are inevitably formed. Interestingly, the desorption of chlorine species over Ru-based catalysts can be dramatically promoted under humid conditions, suppressing the formation of hazardous polychlorinated byproducts effectively (over 3 times lower under 2 vol % of water vapor conditions than the dry conditions). Results reveal that the presence of Ru enables Cl species transformation and dissociation over the catalyst surface that fosters the destruction of 1,2-DCE on adjacent Mn/Co sites under humid conditions, providing a rationale for high catalytic activity of the catalysts and paving the way for industrially relevant CVOC benign destruction.