Engineering Ru/MnCo₃O_x 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/MnCo3O x 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.

Simultaneously Constructing Active Sites and Regulating Mn–O Strength of Ru‐Substituted Perovskite for Efficient Oxidation and Hydrolysis Oxidation of Chlorobenzene

“…It has to be noted that no polychlorinated benzenes are detected under the detecting condition of gas chromatograph, which is quite different from the results of other reports. [ 22 , 38 ] The concentrations of the formed byproducts increase first and then decline along with the rise of reaction temperature. The maximum concentrations of these byproducts are lower than 10 ppm except for CCl 4 (close to 20 ppm).…”

“…These further demonstrate that the substitution of Ru weakens Mn–O bond strength more effectively, resulting in LMRO performing better reducibility that is in favor of CB oxidation. [ 38 ]…”

“…These further demonstrate that the substitution of Ru weakens Mn-O bond strength more effectively, resulting in LMRO performing better reducibility that is in favor of CB oxidation. [38] O 2 temperature-programmed desorption (O 2 -TPD) can provide dependable information about the mobility of oxygen species (Figure 3b). The major desorption peak between 450 and 750 °C is assigned to the desorption of O latt .…”

Electron Transfer Trade-offs in MOF-Derived Cobalt-Embedded Nitrogen-Doped Carbon Nanotubes Boost Catalytic Ozonation for Gaseous Sulfur-Containing VOC Elimination

“…Environmental humidity has an important influence on the performance and lifetime of catalysts . In Figure d, the Co@NCNT-800 catalyst had the worst elimination performance at 0% relative humidity (RH); when RH increased to 30% or 60%, the removal efficiency of CH 3 SH by the catalytic ozonation process increased by about 22.56%.…”

“…Environmental humidity has an important influence on the performance and lifetime of catalysts. 42 In Figure 2d, the Co@ NCNT-800 catalyst had the worst elimination performance at 0% relative humidity (RH); when RH increased to 30% or 60%, the removal efficiency of CH 3 SH by the catalytic ozonation process increased by about 22.56%. In the catalytic ozonation process, appropriate humidity conditions are conducive to the participation of H 2 O in the catalytic reaction, which is conducive to the generation of •OH with stronger oxidation ability (•OH E 0 = +1.9 to +2.7 V NHE ), 43 thereby accelerating the oxidative elimination of CH 3 SH.…”