DFT Study On Metal Na Catalyzed Water

Water Gas Shift Reaction is an important reaction process for hydrogen production from coal and natural gas.Adding appropriate catalyst can effectively improve hydrogen production efficiency.Zhundong coal is rich in reserves and has a high content of sodium alkali metal,which has catalytic effect on Zhundong coal gasification and Water Gas Shift Reaction and can improve the efficiency of producing hydrogen from Zhundong coal.Density functional theory to describe the electronic structure of the reaction system from the microscopic view,system information such as energy and reaction intermediate state,therefore,on the basis of density functional theory calculation of quantum chemistry study sodium metal catalytic water-gas transformation from the atomic level,can promote the micro mechanism of the sodium metal catalytic water-gas transformation.In this thesis,density functional theory(DFT)calculation is used to construct and optimize the model of non-catalytic and metal sodium catalyzed Water Gas Shift Reaction from the micro level,search the optimal reaction path,and determine the energy barrier change of each elemental reaction,the energy span of the whole path and the reaction mechanism.The results show that the metal sodium can obviously reduce the reaction energy barrier during the Water Gas Shift Reaction.The adsorption between sodium atoms and water molecules is strong,and the hydrogen-oxygen bond in water can be broken through the lowest energy change to accelerate hydrogen transfer.The presence of sodium ions makes the reaction produce more intermediates,which can lower the reaction energy barrier in the process of hydrogen transfer by combining Na₂CO₃with water.From the perspective of the three reaction paths,whether it is non-catalytic or catalyzed by sodium atom or sodium ion,the Water Gas Shift Reaction experiences H transfer,CO transformation,H desorption,H₂and CO₂generation,and formic acid intermediates are generated.By using Multiwfn to extract the data of calculation process of Water Gas Shift Reaction catalyzed by non-catalytic and metal sodium atoms and sodium ions,the role of spin population and bond level change in Water Gas Shift Reaction was investigated.The results show that the sodium atom forms an open shell in the catalytic Water Gas Shift Reaction,and the reaction activity is improved by increasing the spin density of surrounding atoms in the reaction,reducing the energy density of nearby oxygen and hydrogen,promoting the oxygen transfer and hydrogen removal,and promoting the Water Gas Shift Reaction.In the analysis of bond formation and breaking,it has stronger ability to weaken hydrogen-oxygen bond,promotes the reactivity of water,strengthens the bond forming ability of hydrogen,and is beneficial to hydrogen desorption.The results show that the energy span of Water Gas Shift Reaction catalyzed by sodium atom is small and the catalytic effect is strong.