Controllable Synthesis Of Cerium-titanium Composite Oxide And Its Application In Methanol Conversion

Due to the serious threat of fossil fuel consumption,there is an urgent need for alternative energy sources to achieve modern sustainable development.China's energy structure is characterized by rich coal,lack of oil and less gas.The technology of producing methanol from coal is very mature.Based on this,methanol has gradually developed into an important platform molecule for fuel preparation and chemical production.The selective oxidation of methanol to dimethyl carbonate and the complete oxidation reaction provide a theoretical basis and practical basis for methanol oxidation.The key to the methanol oxidation pathway lies in the development of high performance catalysts.The main research contents of this paper are as follows:The solid solution catalysts of Ce1-xixO2(x=0?0.20)with different molar ratios were successfully synthesized by coprecipitation method.The catalysts were coated on honeycomb ceramics to form monolithic catalysts.The selective oxidation synthesis of methanol was studied.The catalytic performance of dimethyl carbonate(DMC)reaction was characterized by TEM,XRD and XPS.The results show that the doping of titanium ions changes the crystal structure parameters of the Cerium-titanium catalyst and forms a solid solution.The Ce0.90Ti0.10O2 catalyst has the highest specific surface area and Ce3+ content of 189.2 m2/g and 19.56,respectively.The activity test results show that when the molar doping amount of titanium is 10%,the reaction temperature is 140?,the reaction pressure is 2.4 MPa,the reaction time is 9 h,the catalyst activity is the best,and the methanol conversion rate is as high as 25.23%.Under the optimal reaction conditions,the spherical Cerium-titanium catalyst has higher activity than the rod-shaped catalyst because of its high specific surface area and Ce3+content.The solid solution catalysts with different molar ratios of Ce1-xTiO2(x=0?0.20)were synthesized by hydrothermal method.The catalysts were synthesized into monolithic catalysts.The selective oxidation of methanol to dimethyl carbonate(DMC)was studied.The catalytic performance was characterized by TEM,XRD and XPS.The results show that the doping of titanium ions changes the crystal structure of the ruthenium titanium catalyst,and the morphology of the nanorods changes from slender to short.The Ce0.95Ti0.05O2 catalyst has the highest content of Ce3+,which gives the catalyst stronger redox performance.The activity test results showed that the molar doping amount of titanium was 5%,the reaction temperature was 140?,the reaction pressure was 2.2 MPa,the reaction time is 12 h,the catalyst activity was also the best,and the methanol conversion rate was 21.32%.The PdCu spherical nanoparticles with uniform morphology were successfully synthesized by polyol reduction method,and the average particle size was 7.4 nm.The active particles were successfully loaded onto different amounts of Cerium-titanium composite oxide supports by different impregnation methods to obtain different supported PdCu bimetallic catalysts,which were coated on honeycomb ceramics to form monolithic catalysts.Its catalytic performance for complete oxidation of methanol was characterized by SEM-EDS,XRD and XPS.The results show that the bimetallic catalyst with spherical Ce0.90Ti0.10O2 composite oxide as the carrier has the lowest T50,T90 and ?T,which are 110?,150? and 40?,respectively,which is far superior to the literature under the same conditions.