Theoretical Investigation Of Electrocatalytic Performance Of The Two-dimensional Graphdiyne-based Materials Supported Transition Metals

Since 2010,the first successful preparation of graphdiyne（GDY）has attracted widespread attention from researchers.As a new two-dimensional nanostructure material,GDY has special electronic properties,large specific surface area,uniform pore structure and excellent electrical conductivity,which can be used as an ideal electrocatalyst carrier and has certain application prospects in photoelectric catalysis and new energy fields.GDY as the substrate of electrocatalysts has been widely reported in experimental and theoretical study,and the electronic structure of graphdiyne can be adjusted by anchoring metal single atoms/metal clusters on the large pore size of GDY,and its band structure can be adjusted to further improve the catalytic performance of the catalyst.Based on Density Functional Theory（DFT）,this paper systematically explores the loading of transition metal single atoms/clusters onto the pores of GDY,and explores the active origin of different catalytic reactions by regulating the electronic properties of graphdiyne,so as to find the internal causes affecting different electrocatalytic reactions.Therefore,we mainly anchor transition metal nickel（Ni）clusters with specific geometries and electronic structures on GDY to study their catalytic mechanism and active origin of carbon dioxide reduction reaction（CO₂RR）.and anchoring single-atom metals into GDY pores to find suitable single-atom catalysts（SACs）to explore the catalytic activity and selectivity of reducing nitrate（NO₃^-）to ammonia（NH₃）.In this paper,our mainly research content is divided into the following two parts:（1）The electrocatalytic potential of CO₂RR was explored by anchoring Ni clusters on GDY monolayer materials（Ni_x/GDY,x=1-6）.The results show that the Ni clusters which anchored on GDY exhibit high stability and excellent electronic properties due to the strong interaction between Ni atoms and sp hybridized C atoms.Among them,the anchored Ni₄ clusters exhibit high CO₂RR catalytic activity and medium C-C coupling kinetic barrier.The main products in the CO₂RR process are methane（CH₄）,ethanol（C₂H₅OH）and propanol（C₃H₇OH）.Therefore,by controlling the number of Ni atoms in the nanocluster,it can be used as an efficient and highly selective CO₂RR electrocatalyst.（2）By anchoring a series of monatomic metals（TM/GDY）on GDY as an electrocatalyst for nitrate reduction reaction（NO₃RR）.By systematically analyzing the activity and selectivity of TM/GDY,Os/GDY is considered to be an ideal NO₃RR catalyst with a low limiting potential as low-0.37 V during the reaction and has a great inhibitory effect on competing reactions.In addition,a volcanic plot was established according to the scaling relationship of the adsorption free energy of various intermediates,and the origin of the catalytic activity of NO₃RR is well illustrated by the descriptors of the adsorption intensity and charge transfer of NO₃^*species.Our results not only propose a NO₃RR electrocatalyst to improve ammonia synthesis,but also provide insight into the mechanism of the NO₃RR process.