Rational Design Of Electrocatalysts For Small Molecule Conversion

The rapid development of the world relies heavily on traditional fossil fuel as energy supply,which has brought lasting and adverse effects on the environment and climate.To this end,the realization of energy conversion and value upgrading of small molecules based on electrocatalytic processes will help build a sustainable society.Among them,the carbon monoxide coupling and reduction,nitrogen reduction,as well as nitrogen with carbon monoxide coupling and reduction are promising electrocatalytic conversion processes,and have attracted much attention.These processes can achieve green and sustainable production of high value-added C₂products,ammonia and urea under mild conditions,which is of great significance for alleviating the energy and climate crisis and promoting the vigorous development of industry and agriculture.In this regard,the key is to design and develop efficient and highly selective electrocatalysts,which are closely related to the performance of catalytic reactions.In this work,by means of density functional theory（DFT）calculations,we theoretically explored the effect of the coordination environment around the active site on the nitrogen reduction reaction,and the promotion of multiple active sites on the C-C coupling and C-N coupling process.These results are as follows:（1）Based on the synergistic effect between the TM and B active sites in the designed TM-B@BP catalysts,CO molecules can be feasibly coupled into the key COCO^*-dimer in terms of thermodynamics and kinetics,which is subsequently reduced to the high value-added ethanol,ethylene and ethane products.Three designed catalysts exhibited high catalytic activity,as well as high selectivity against competing C₁ products and hydrogen evolution reactions.（2）The local coordination environment of Mo-based single atom can be changed by the four atoms of B,C,N and O,achieving the regulated performance for nitrogen reduction reaction.Among all candidate catalysts,Mo B₃O is predicted to be the most promising NRR electrocatalyst with a low limiting potential of-0.34 V along the enzymatic pathway.Meanwhile,it can also well inhibit the competing hydrogen evolution reaction,showing excellent selectivity.（3）A series of transition metal atoms are anchored on the porous BN nanosheets to form asymmetric three-active sites with adjacent two B atoms.It can fully activate N₂ molecule and achieve the coupling of N₂ and CO through the SWEP effect.After screening,Fe/p-BN and Co/p-BN systems stand out as promising candidates with high activity（-0.63 and-0.66 V）,high selectivity,and low kinetic energy barrier for driving C-N coupling toward electrochemical synthesis of urea.