Enhanced Water Resistance and Catalytic Performance of Ru/TiO₂ by Regulating Brønsted Acid and Oxygen Vacancy for the Oxidative Removal of 1,2-Dichloroethane and Toluene

Abstract

The compositions of volatile organic compounds (VOCs) under actual industrial conditions are often complex; especially, the interaction of intermediate products easily leads to more toxic emissions that are harmful to the atmospheric environment and human health. Herein, we report a comparative investigation on 1,2dichloroethane (1,2-DCE) and (1,2-DCE + toluene) oxidation over the Ru/TiO 2 , phosphotungstic acid (HPW)-modified Ru/TiO 2 , and oxygen vacancy-rich Ru/TiO x catalysts. The doping of HPW successfully introduced the 1,2-DCE adsorption sites to promote its oxidation and exhibited outstanding water resistance. For the mixed VOCs, Ru/HPW-TiO 2 promoted the preferential and superfluous adsorption of toluene and resulted in the inhibition of 1,2-DCE degradation. Therefore, HPW modification is a successful strategy in catalytic 1,2-DCE oxidation, but Brønsted acid sites tend to adsorb toluene in the mixed VOC oxidation. The Ru/TiO x catalyst exhibited excellent activity and stability in the oxidation of mixed VOCs and could inhibit the generation of byproducts and Cl 2 compared with the Ru/HPW-TiO 2 catalyst. Compared with the Brønsted acid modification, the oxygen vacancy-rich catalysts are significantly suitable for the oxidation of multicomponent VOCs.

Boosting the Catalytic Performance of Volatile Organic Compound Oxidation Over Platelike MnO2/CoAlO Catalyst by Weakening the Co–O Bond and Accelerating Oxygen Activation

“…MnO 2 /CoAlO-P had good cycling stability and long-term stability (Figures c,d and S6), and the catalytic activity of MnO 2 /CoAlO-P remained unchanged over 10 cycles and a subsequent long-term stability test for at least 80 h at 190 and 168 °C. Water vapor adsorbed on the catalyst can cover and block the active sites, leading to the deactivation of the catalyst. , Thus, the catalytic stability of MnO 2 /CoAlO-P in the presence of water vapor needs to be considered. As shown in Figure e, when 5.5 vol % water vapor was introduced to the reactant gas stream at 190 °C, acetone conversion decreased from ∼93% to ∼86%, which might be due to competitive adsorption between water vapor and acetone molecules .…”

“…Water vapor adsorbed on the catalyst can cover and block the active sites, leading to the deactivation of the catalyst. 30,31 Thus, the catalytic stability of MnO 2 /CoAlO-P in the presence of water vapor needs to be considered. As shown in Figure 2e, when 5.5 vol % water vapor was introduced to the reactant gas stream at 190 °C, acetone conversion decreased from ∼93% to ∼86%, which might be due to competitive adsorption between water vapor and acetone molecules.…”

Synergistic Effect of Reactive Oxygen Species in Photothermocatalytic Removal of VOCs from Cooking Oil Fumes over Pt/CeO2/TiO2

“…Compared with the alone hexanal-TPD result, the temperature of hexanal desorption was shifted backward by 20 °C. Therefore, it is reasonable to infer that heptane and hexanal on the catalyst inhibit each other’s adsorption, which leads to a drop in photothermocatalytic performance …”

“…Therefore, it is reasonable to infer that heptane and hexanal on the catalyst inhibit each other's adsorption, which leads to a drop in photothermocatalytic performance. 10 The GC−MS technique was employed to measure the changes of organic products formed over Pt/CeO 2 /TiO 2 with temperature change under the synergistic photothermocatalytic conditions. The results show that the catalytic oxidation process of the VOC mixture was more complex than the photothermal heptane or hexanal (Figure S19) oxidation.…”

“…Inevitably, a large quantity of water vapor is accompanied. , The current eliminating cooking oil fumes methods (including mechanical purification, electrostatic deposition, washing-absorption, and filtration-absorption) mainly focus on the purification of oil droplets and particles in oil fumes, while the elimination of VOCs in the fumes is limited. Synergistic photothermocatalytic oxidation technology , uses renewable solar energy resources to assist thermocatalysis, , resulting in a synergistic effect to further decrease the reaction temperatures, which is of great significance for VOC elimination and CO 2 emission reduction . The development of photothermal catalysts with good stability and water-resistant performance is one of the key challenges in the purification of VOCs derived from cooking oil fumes.…”