Study On Au-MO_x/BN Catalytic Oxidation Of Ethyl Acetate And Its Sintering Resistance

Volatile organic compounds（VOCs）come from a wide variety of sources and are precursors for the formation of ozone and PM_2.5.Among them,ester VOCs have a stable structure and are not easily purified.Controlling the emission of ester VOCs is of great practical significance for improving the current situation of air pollution.Currently,most enterprises use precious metal catalysts with Pt and Pd as active components to treat ester VOCs.However,the content of Pt and Pd in nature is much lower than that of Au.In order to implement the theory of sustainable development,it is urgent to develop efficient and stable Au based catalysts.In this paper,Au/BN catalysts were modified by loading non noble metal oxides and doping non-metal atoms.Ethyl acetate and carbon monoxide were used as target products to evaluate the effects of loading different types of non noble metal oxides and loading amounts on the performance and structure of the catalyst.The effect of doping non-metal atoms on the sintering resistance of the catalyst was investigated.1)Firstly,the Au/BN（Au content is 1wt%）catalyst was prepared by ammonia precipitation method.Then,the Au-MO_x/BN（M=Fe,Cu,Ce）catalyst was prepared by impregnation method with 7wt%Fe O_x,Cu O,and Ce O_x loaded.The oxidation performance of the catalyst was evaluated using ethyl acetate as the target pollutant.Au-Fe O_x/BN was found to have the best catalytic activity,with T₅₀（temperature at 50%pollutant conversion rate）and T₉₀（temperature at 90%pollutant conversion rate）for the oxidation of ethyl acetate at 190℃and 210℃,respectively.The relationship between catalyst performance and structure was studied through characterization methods such as TEM,XRD,H₂-TPR,XPS,and EA-TPD,and the reaction mechanism of Au-MO_x/BN catalytic oxidation of ethyl acetate was analyzed.2)Au-n Fe O_x/BN（n=1,3,5,7,10）catalysts were prepared by loading 1,3,5,7,and10wt%Fe O_x onto Au/BN using impregnation method,and were used for catalytic oxidation of ethyl acetate and carbon monoxide.It was found that when the loading amount was 7wt%,the catalyst had the best catalytic activity for the oxidation of ethyl acetate.When the load is higher than 3wt%,the CO oxidation activity of the catalyst is similar.Analyze the influence of Fe O_x loading on the structure and performance of the catalyst through physical and chemical characterization methods,and study the differences in the reaction mechanism of catalytic oxidation of CO and ethyl acetate by the catalyst.3)The Au-3Fe O_x/BN catalyst was selected,with CO as the target pollutant,and the gas volume space velocity and CO₂ concentration were changed to evaluate the CO oxidation performance of the catalyst.Explore the effects of gas flow rate and gas concentration on the performance of Au-Fe O_x/BN catalysts.The results indicate that as the gas flow rate and concentration increase,the oxidation activity of the catalyst decreases.4)S-BN and C-BN supports were prepared by heat treatment method,and Au/S-BN and Au/C-BN catalysts were prepared by deposition precipitation method.The catalysts were calcined at high temperature,and the effects of S and C doping on the sintering resistance of Au/BN catalysts were studied through TEM and XRD results.It was found that the doping of C and S improved the sintering resistance of Au/BN.In addition,the activity of the Au-Fe O_x/S-BN catalyst after high-temperature calcination was tested with CO as the target pollutant,and it was found that the Au-Fe O_x/S-BN catalyst showed the best activity,proving that S doping reduced the impact of high temperature on the Au catalyst and improved its sintering resistance.