Study On Polymerization Of Carbon Monoxide And Carbon Monoxide With Impurities At Different Thermo Conditions

Mechanical energy could be stored in a material with the alteration of chemical bonds within it by compression,which is an important idea to produce high energy density materials?HEDM?.Polymer nitrogen?p-N?is an example of the pressure induced HEDM,however,it is to harsh to produce p-N,and the product is not easly preserved.CO has the same molecular weight,electron number,and crystal structure,and there were experiemtal proof that CO could be polyrized at relatively low pressure compared with N₂,and lease energy with light stirring.It is important to understand the synthesis path and product of pressure induced polyrized CO.We used the ab intio molecular dynamics to simulate the polymerization of CO at different thermodynamic conditions.We simulate the polymerization with different initial phases,different supercell sizes,different temperatures,contain different concentrations of H₂,and CO doped with other molecules and find:1.By comparing the?and?phase CO as the initial structure for MD simulation,we found that?-CO as the initial phase is more conducive to the polymerization of CO.With different supercell sizes as the initial structure,we find that the supercell size has a great influence on the aggregate structure.When the supercell contains 108CO's,the pressure when starting polymerization is between 10 and 15 GPa,when the supercell contains 64 CO,the pressure when starting polymerization is 10 GPa.When the pressure exceeds 15 GPa,the effect of supercell size on polymerization is reduced.For the effect of different temperatures,we mainly simulated the polymerization of CO at 300 K,350 K and 400 K.We found that the pressure at the start of polymerization decreases with increasing temperature,but it is obvious that the effect of temperature decreases when the pressure exceeds 15 GPa.2.First-principles molecular dynamics studies were conducted on a mixture of CO doped with different concentrations of H₂.It was determined that the pressure at which CO containing different concentrations of H₂ started to polymerize was very different.When the concentration of H₂ contained is between 2.11%and 6.22%,the polymerization pressure of CO can be reduced to 5 GPa.The polymerization process can be simply described as:when the pressure is 1 GPa,H₂ participates in the reaction to form various small molecules,and when the pressure is continued to 5 GPa,the small molecules are connected together to form a large molecule with a carbon skeleton,as the pressure continues to increase the carbon chain grows continuously,then forms a ring structure,and finally forms a chain-like disordered polymer connected to the ring structure.However,when the pressure reaches 15 GPa,the main skeleton of the polymer is basically formed.As the pressure continues to increase,the polymer skeleton does not change.The important significance of H₂ in the polymerization process can be summarized as follows:First,H₂ reduces the polymerization conditions by participating in the formation of small molecules.Second,H₂ maintains the stability of the polymer structure through passivation during the depressurization process.Finally,Doping H₂ to synthesize materials is an effective method.3.Doping N₂ and NH₃ in CO can effectively reduce the pressure during polymerization.The pressure at the start of polymerization after the impurity is incorporated is 5 GPa.The above research and results have deepened the understanding of the thermodynamic conditions such as temperature and pressure required to prepare high-energy substances with CO as raw materials,and the effect of H₂ doping on CO polymerization.