Catalytic Performance Of CuO/CeO₂ Nanorod Catalysts Synergistically Prepared With Non-equilibrium Plasma For Volatile Organic Compounds Oxidaton

Volatile organic compounds（VOCs）are not only deemed to be sources of ozone and PM2.5 pollutants but also threats to human health,due to their complex properties and various causations.Thus,the controlling of VOCs emissions has been the focus and challenge of improving the atmospheric quality.Catalytic oxidation is capable of converting VOCs to CO₂ and H₂O drastically under low temperature,which is an efficient and energy-saving technology with no NOx formed,for the goal of“Emission peak”and“Carbon neutrality”.For catalytic oxidation,catalysts are the crucial factors.Among all the materials,transition metals attract numerous attentions in that they have extraordinary reducibility and oxygen activation ability compared with noble metals.As an environmental-friendly treatment method,plasma has significant research values and promising prospects.In this paper,CuO/CeO₂ catalysts were synthesized to investigate the optimal loading ratio via non-equilibrium plasma,and the impacts of plasma and glucose during the preparation on the activity and selectivity of catalytic toluene oxidation as well as the physicochemical properties of the catalyst were also discussed.（1）By controlling the loading ratio of Cu,Cu Ce-X（X=1,2,3,4 and 5）catalysts were prepared through non-equilibrium plasma coupled with impregnation method.It is indicated that Cu Ce-4 has the best catalytic activity with T₉₀（265℃）a little lower than that of Cu Ce-5（268℃）.Combined with characterizations,this can be attributed to the smaller crystalline structure,more oxygen vacancies and better reducibility of Cu Ce-4.Besides,strong interaction between Cu and Ce further promotes the activity.（2）Glucose-containing and glucose-free CuO/CeO₂ nanorods were obtained via non-equilibrium method for toluene oxidation.As the results show,glucose may inhibit the activity of the catalysts since it cannot be completely decomposed during the preparation.The synergistic effect between CuO active species and CeO₂ supports can be distinctively facilitated by means of non-equilibrium coupled with traditional high temperature calcination,contributing to highly-dispersed CuO.Moreover,non-equilibrium is in favor of Cu⁺/Cu²⁺and Ce³⁺/Ce⁴⁺pairs,consequently forming more oxygen vacancies.During the oxidation of toluene,abundant oxygen vacancies can accelerate the adsorption and activation of gas oxygen,leading to promoted catalytic activities.The Mars-van Krevelen（Mv K）mechanism can properly illustrate the toluene oxidation reaction over CuO/CeO₂ nanorods.