Preparation Of Supported Palladium Catalyst And Its Catalytic Hydrogenation Preferormance

Hydrogen peroxide,as a green chemical,is widely used in daily life.Its preparation methods mainly include anthraquinone method,isopropanol method,electrolysis method and direct synthesis of O₂ and H₂O.Anthraquinone method accounts for more than 95%of all hydrogen peroxide preparation methods due to its low energy consumption,low cost and high industrial efficiency.Palladium catalyst as the preferred choice of anthraquinone system has been deeply discussed by researchers.The research on palladium catalyst is mainly divided into support modification and active metal doping optimization,but the research on enhancing catalytic activity by adding additives to provide oxygen vacancy has not been seen in anthraquinone system.In addition,anthraquinone production of hydrogen peroxide is the main limiting factor is the control of gas-liquid mass transfer,which is a typical rapid reaction.Therefore,choosing a suitable reactor to solve the mass transfer problem is also the key to improve the reaction efficiency of the production method.In view of the above problems,this work mainly made innovative improvements in two aspects:（1）Adding cerium dioxide as a cocatalyst to provide oxygen vacancies,improve the adsorption configuration of anthraquinone molecules,and enhance the reaction activity.At the same time,the consumption of precious metal palladium is greatly reduced and the production cost is saved.（2）The fixed bed microreactor is used as the reaction device.By adjusting the reaction conditions and calculating and analyzing the kinetics,the difficult mass transfer problem of hydrogen peroxide production system by anthraquinone method is solved.Finally,the conversion rate of Pd/Al₂O₃ catalyst designed in this work is more than 2 times higher than that of commercial catalysts and literature reports,while the amount of precious metal is less than 0.1%,only 1/3 of the literature reports.Pd-Ce O₂/Al₂O₃through the addition of cerium,on top of this again improve the production efficiency,not only increase the reaction activity,but also solve the mass transfer problem.It lays a solid foundation for anthraquinone production of H₂O₂ system again.