Study On The Adsorption Of Guaiacol On The Surface Of Nickel-iron Bimetal

Energy issues have always been a hot topic that scientists have paid close attention to.The development of efficient,inexpensive,and environmentally friendly renewable energy utilization technologies is the current research trend in the energy field.As an important component of lignocellulosic biomass,lignin has been favored by many scientists because of its special aromatic composition.In this paper,guaiacol was selected as the model compound of lignin for research.In the field of catalysis,transition metal catalysts have a special arrangement of extranuclear electrons.In this paper,nickel with a good hydrogenation effect and iron-philic metal iron are used as catalysts for research.As the first step of chemical reaction,adsorption is of great significance for studying the complete interface interaction.In this paper,based on the density functional theory,guaiacol was studied on the adsorption energy,bond length change,differential charge density,state density of guaiacol in monometallic Ni(111)and bimetallic NiFe(111)catalysts.The purpose is to study how the adsorption behavior affects the electronic structure changes of guaiacol,and provide a theoretical basis for the selection and preparation of highly efficient catalysts.The main conclusions are as follows:The adsorption of guaiacol on the surface of Ni(111)is chemical adsorption.Ni has a repelling effect on the hydroxyl and methoxy groups in guaiacol.Each bond of guaiacol on the Ni surface is elongated,and the change in the bond length of the carboncarbon bond on the aromatic ring is greater than that between the CO bond.It can be speculated that the Ni(111)surface and guaiacol The interaction between the aromatic rings is relatively strong,and it is inferred that the guaiacol after adsorption is easier to hydrogenate.The adsorbed hydroxyl group is more stable than the methoxy group,which is beneficial to the removal of methoxy groups for the purpose of deoxygenation.There is a large amount of electron transfer on the surface of guaiacol and the single metal Ni(111);hydrogen atoms in the guaiacol close to the metal surface lose electrons;the electrons are rearranged both inside and outside the guaiacol molecule.Guaiacol obtains electrons during the adsorption process and is negatively charged,the metal surface loses electrons and is positively charged;after stable adsorption,the hydroxyl group is negatively charged,the methoxy group is negatively charged after stable adsorption,and the aromatic ring is positively charged after stable adsorption.In the system after adsorption,guaiacol has the largest contribution in the low energy band,and metal Ni has the largest contribution in the electron orbit range of-5～0 e V;the electrons of guaiacol after adsorption are mainly distributed in the range of-20.2～-4.1 e V.The increase of p orbital electrons decreases;the electrons on the metal surface after adsorption decrease,and it is mainly transferred from the-3.7～-0.5 e V interval on the d orbit to the adsorption space.The adsorption of guaiacol on the surface of NiFe(111)is chemical adsorption;compared with the single metal,the interaction between guaiacol and bimetallic NiFe is stronger;both the guaiacol molecule and the molecule Rearrangement of electrons;on the metal surface,Ni transports electrons to guaiacol,while Fe atoms get electrons from the guaiacol side.Guaiacol obtains electrons during the adsorption process on the bimetallic surface and is negatively charged;the metal surface loses electrons and is positively charged;after stable adsorption,the hydroxyl group is negatively charged,the methoxy group is negatively charged after stable adsorption,and the aromatic ring is stable in adsorption After being positively charged;the state density of the metal in the system contributes the most.The state density of nickel and iron in the bimetal is mainly occupied by the d orbit;compared with the single metal,the electron distribution interval of the nickel in the bimetal is slightly increased,indicating the distribution range of electrons when the surface electrons are rearranged Increase;the electrons of nickel in the bimetal decrease,and the electrons in nickel transfer to iron,indicating that the external electronic structure changes when the bimetal is formed.