Tuning The Magnetism And Single Atom Catalytic Activity In Compensated N-p Codoped Graphene/Transition Metal System

Since graphene was successfully fabricated in 2004,it has attracted tremendous attention due to its unique structural,mechanical,and electronic properties.The long spin coherence time and weak intrinsic spin-orbit coupling make graphene a promising material for spintronic applications.Generating ferromagnetism or most ideally,long-range ferromagnetism in graphene is important to the development of graphene-based spintronics.In the past ten years,there are a number of mechanisms that can make graphene magnetic.Nevertheless,there is an inescapable fact that the linear energy at dirac point disappears at the same time.It means that,the magnetic graphene tends to lose its exceptional physical properties.By using first-principles calculation methods,we propose a new scheme based on compensated n-p codoping and non-covalent ?-? stacking with F4-TCNQ,to engineer some hybrid structures of Fe/graphene/F4-TCNQ.Our results firstly show that F4-TCNQ adsorption on graphene can preserve the original electronic properties of graphene.Moreover,F4-TCNQ adsorption on graphene can lead it to p-type,which is in agreement with experimental finding.Then,very stable hybrid Fe/graphene/F4-TCNQ system due to compensated n-p codoping interaction is engineered.Further calculations reveal that a long-range and strong ferromagnetic coupling of two Fe adatoms is realized by F4-TCNQ exchange interaction in the hybrid Fe/graphene/F4-TCNQ system.This study provides a new method to realize ferromagnetic graphene and preser ve its extraordinary properties.Besides,noble-metal catalysts on a substrate with a high surface area can achieve high activity in a large number of important chemical reactions.Whereas,the problem such as high cost and limited supply of noble metals significantly reduce the demand for them.The size of metal particles and the selection of sutable support materials are very important.The activity of catalyst can be improved by downsizing the size of nanoparticles to sub-nano scale or even single atom.However,metal atoms due to the high surface free energy usually lead to an aggregation of metal atoms into big clusters on substrates.The large specific surface areas,and novel electronic and thermal properties make graphene a promising support material.Theoretically,the single-atom Au,Pt,Pd and Cu embedded graphene systems are predicated to have high catalytic activity.However,the realization of vacancies in such material is very difficult up to now.Therefore,it is necessary to explore new methods to realize high efficiency single atom catalyst.By using first-principles calculation methods,we propose a new scheme based on compensated n-p codoping to engineer stable hybrid structures of B/Cu/graphene and B/Fe/graphene.The calculated results show that the non-noble single-atom Cu and Fe exhibit highly catalytic activity for CO oxidation,and the energy barrer is low.This opens a new avenue to realize single atom catalyst.