Molecular Simulation Of Carbon Dioxide Hydrogenation Catalyzed By Bimetallic M-Cu-MOFs Materials

In recent years,the concept of Carbon Capture and Utilization?CCU?has gradually come into our view.Using CO₂ as the raw material for chemical production can not only alleviate the consumption of fossil energy,but can also help to mitigate the greenhouse effect.CO₂ hydrogenation is one of the most widely studied way of CO₂ resource utilization.Metal-Organic Frameworks have great potential on CO₂ capture thanks to their rich internal pore structure and high adsorption capacity.It also has good application prospect in heterogeneous catalysis because of their extremely high specific surface area,which is advantageous to the high dispersion of active sites and stable properties;And excellent structural control performance,which enrich the diversity of MOFs materials.In this paper,the process of CO₂ adsorption,activation and hydrogenation on transition metals doped M-Cu-BTC MOFs is studied using DFT method.The adsorption properties of CO₂ on 20 kinds of M-Cu-BTC materials?M=Cr,Mn,Fe,Co,Ni,Cu,Zn,Mo,Tc,Ru,Rh,Pd,Ag,Cd,W,Re,Os,Ir,Pt,Au?are calculated.It is found that M-Cu-MOFs doped with molybdenum or tungsten can activate and bend the CO₂ molecules.The difficulty of CO₂ hydride&proton reactions on molybdenum and tungsten are investigated.It is found that the introduction of the second metals accelerate the activation of CO₂,and reduced the energy barrier of CO₂ hydrogenation compared to its on pure Cu-BTC.Tungsten can activate CO₂ better than molybdenum,when the dissociate H*atoms are existing,the energy barrier of CO₂ hydride reaction is only0.30 eV,and the reaction is exothermic for 0.76 eV.The activation energy and reaction heat of each element steps in methanol synthesis reaction network on W-Cu-BTC are calculated.The most likely reaction path is obtained as CO₂*?CO*?HCO*?HCOH*?H₂COH*?H₃COH*.The element step of HCO*proton is the rate controlling step of this process,in which the co-adsorption and reaction need to overcome an energy barrier of 1.22 eV and release heat of 0.38 eV.The results of this paper provide a preliminary judgment for the possibility of CO₂ hydrogenation on W-Cu bimetallic MOFs,and provide a preliminary idea for the future catalyst design work.