Preparation Of Spherical Cerium Based Catalyst And Its Catalytic Oxidation Performance Of Ethyl Acetate

The harm of volatile organic compounds to the environment and human body can not be underestimated.At present,catalytic oxidation is one of the main means to deal with volatile organic compounds,and its core technology is to improve the catalytic oxidation performance of catalysts.Cerium oxide has a strong ability to store oxygen and release oxygen,and cerium is the earth’s most abundant rare earth element.Therefore,in this paper,using ethyl acetate as the target pollutant,efficient spherical cerium based catalysts was developed,and the effects of metal-support interaction and heterogeneous interface synergies on catalysts performance were investigated.The main contents and conclusions are as follows:（1）Study on preparation of Ru/CeO₂ catalysts and the performance of ethyl acetate for catalytic oxidation.CeO₂ microspheres were prepared by hydrothermal synthesis method,and Ru/CeO₂ composite catalysts was prepared by depositprecipitation method with Ru noble metal particles on the surface of CeO₂ microspheres.The catalytic oxidation activity of Ru/CeO₂ to ethyl acetate was tested,and its physicochemical properties were characterized and analyzed.The results showed that the activity of Ru/CeO₂ was superior to CeO₂.Ru/CeO₂ catalysts formed the interaction between precious metal and ceria,which increased the reactive oxygen species compared with CeO₂,enhanced the oxygen storage and release capacity,and promoted the performance of ethyl acetate oxide in low temperature catalysis.Among several catalysts samples with different amounts of Ru loading,when Ru content was 1 wt.%,the catalytic oxidation of ethyl acetate was better,and T₉₀(T₉₀ refers to the temperature required to convert 90%ethyl acetate into CO₂)was reduced by 28.5℃compared with CeO₂.Appropriate Ru loading on the surface of CeO₂ microsphere was more conducive to the transfer between metal and support.（2）Study on interfacial effect of core-shell CeO₂@MnO₂ catalysts and the performance of ethyl acetate for catalytic oxidation.Spherical cerium oxides CeO_x-1 and CeO_x-2 obtained under two different conditions were used to control the growth of sheet MnO₂ on the surface of spherical cerium oxides by hydrothermal reaction.Core-shell CeO₂@MnO₂ materials with different interfacial microenvironments were constructed and used for catalytic oxidation of ethyl acetate performance test.The results showed that the properties of the two CeO₂@MnO₂ core-shell materials were superior to those of CeO₂ and MnO₂ monomers,which was mainly due to the increase of reactive oxygen species at the interphase interface of cerium manganese oxides,which improved the catalytic activity.Among the two core-shell materials,CeO₂@MnO₂-1 had the better catalytic activity,which was mainly due to the better interfacial interaction effect in CeO₂@MnO₂-1,which enabled more manganese ions to infiltrate into cerium oxides and increased the ratio of Ce³⁺,Mn³⁺and reactive oxygen species.（3）Study on the metal-support synergism of Ru/CeO₂@MnO₂ catalysts and the performance of ethyl acetate for catalytic oxidation.By using vitamin C and sodium borohydride reduction methods,single atom and particle Ru were loaded on the surface of CeO₂@MnO₂ active support to obtain single atom Ru₁/CeO₂@MnO₂ and particle Ru _NP/CeO₂@MnO₂ catalysts,and their catalytic oxidation properties for ethyl acetate were tested.The effect of metal-support synergism on the surface microenvironment of Ru/CeO₂@MnO₂ catalysts was analyzed.The results showed that the performance of the catalysts supported by Ru was better than that of CeO₂@MnO₂,and the monatomic Ru supported sample Ru₁/CeO₂@MnO₂ had more surface oxygen vacancies and higher oxygen mobility than the particle Ru supported sample Ru _NP/CeO₂@MnO₂,showing better catalytic oxidation performance at low temperature.