Density Functional Theoty Study On The Reaction Of Ni-based Oxygen Carrier With CO In Chemical-looping Combustion

In recent years, the global warning problem is increasingly leading to great concern,and chemical-looping combustion（CLC）is got attention as a result of its inherentlyseperating CO₂, reducing NOx, and high combustion efficiency. So, this new combustiontechnology has got deep research by scholars.Ni-based oxygen carrier is the most preferred one. The Density Functional Theory（DFT） was performed on the CASTEP of MS version5.5to investigate the reactivitymechanism of CO with NiO.On the perfect and defect surface of NiO, the CO adsorption was investigated. TheSGGA+U method performed well on the adsorption of CO on the NiO perfect surface.COwas weak-chemically adsorbed on the O vacancy site；The equilibrium configuration of twoCO moleculars adsorption on the NiO could not form CO₂.On the perfect and defect surface of NiO, O₂and O atom adsorption was investigatedrespectively. The results were that: O₂tended to bond with the perfect surface by bondlength of2.395and bingding energy of-1.73ev. however, on the O vacancy surface, theO₂adsorbed on the O vacancy site of the substrate; on the perfect surface, O atom bondedwith the surface by chemisorption no matter any active sites.On the perfect and defect pre-adsorbed O₂and O atom surface of NiO, CO subsequentadsorption was investigated. The results were that: whether perfect and O vacancy surface,on condition that O₂pre-adsorbed, the CO₂could not formed when CO subsequentadsorption. However, on the perfect surface, CO₂could be formed when CO adsorben onthe surface of O atom pre-adsorption.The research revealed the mechanism of CO fuel gas with NiO on the condition ofpresence and absence of O species, and provied the theory basis for the reduction reactivityof NiO oxygen carrier.