Adsorption And Catalysis Of Small Molecules On Penta-graphene

Penta-graphene,due to its unique structural and electronic properties,has a widerange of applications in the fields of nanoelectronic devices,energy storage,gas sensing and molecular catalysis.In this paper,first-principles method based on density functional theory was used to study the adsorption behaviors of CO,NO,CO₂,NO₂,N₂O and N₂on penta-graphene.It was found that the adsorption energy of NO,NO₂and N₂O on penta-graphene can reach 0.207 e V,0.169 e V and 0.406 e V,respectively.In addition,the comparison between the adsorption distance and the amount of charge transfer shows that penta-graphene has a higher sensitivity to nitrogen oxide molecules.While CO and NO molecules can chemisorb on the penta-graphene surface only after overcoming the energy barriers of 0.046 e V and0.037 e V,which provides the possibility for their catalytic reaction on penta-graphene.When CO and NO coexist on the surface of penta-graphene,the redox reaction of CO+NO→CO₂+N,NO+N→N₂O can be realized efficiently.Compared with the energy barrier of 0.970 e V under the Langmuir-Hinshelwood（LH）mechanism,the reaction barrier under Eley-Rideal（ER）mechanism is only 0.375 e V,which is comparable to the oxidation of CO catalyzed by precious metals.In order to understand the whole reaction process,we also analyzed the partial orbital density of states（PDOS）at each step under ER and LH mechanisms.It is worth noting that the migration of N atoms generated in the first step on the surface of penta-graphene is very difficult,and the migration barrier is as high as1.983 e V,which makes the 2CO+2NO→CO₂+2N reaction can be completed on penta-graphene,but the subsequent possible 2N→N₂reaction is difficult to achieve,and eventually N₂O and CO₂products will be formed,on the other hand,because the adsorption energy value of CO₂on penta-graphene is small and N₂O is difficult to disintegrate on the surface of the material,it is easy to desorb CO₂and N₂O on the surface.These results indicate that penta-graphene can be used as both a reaction carrier and an efficient catalyst for CO and NO,and provides a new method for the efficient preparation of N₂O under low temperature.