Adjusting the microenvironment of the electrode surface is one of the effective means to improve the efficiency of electrocatalytic carbon dioxide reduction (ECO2RR). In order to achieve a high conversion rate, the phase interface on the electrode surface should be finely controlled to overcome the limitation of CO2 solubility in aqueous electrolytes.
Based on this,Academician Han Buxing of East China Normal University, Professor Wu Haihong, Jia Shuaiqiang (co-corresponding author) and othersA simple and effective method is reported to construct an electrocatalyst with a superhydrophobic surface microenvironment by co-electrodepositing copper (Cu) and polytetrafluoroethylene (PTFE) on carbon paper (CP) in one step. The superhydrophobic Cu-based electrode exhibits high ethylene (C2H4) selectivity, in H-type cells25 v vs.The Faraday efficiency (Fe) under RHE is 673%, which is 25 times. The use of PTFE as a surface modifier enhanced the activity of Eco2RR and inhibited the hydrogen evolution reaction.
In this paper, the reaction mechanism of CO2 to C2H4 on Cu-CP and Cu-[CF2]N-5-CP catalysts with PTFE was explored by DFT calculation. The charge density difference plots of the Co intermediates binding at Cu(111)-[CF2]N- surfaces indicate that the addition of PTFE reduces the amount of electron transfer and the Co adsorption energy may also be attenuated. In addition, the charge density difference plot of Cu(111)-[cf2]N- also shows charge accumulation between Cu and Co intermediates, which favors the formation of C-C bonds in subsequent reaction steps.
In this paper, the free energy change (δg) of Eco2Rr on Cu-Cp and Cu-[cf2]N-5-Cp catalysts is further calculated. The two reaction pathways are: (i) *CO is hydrogenated to *CHO, followed by the dimerization of two *CHOs to OHCCHO*, and finally reduced to C2H4;(ii) *CO is directly dimerized to OC*CO and then reduced to C2H4. The results show that path (ii) is more advantageous on both electrode surfaces. where the δg of the *CO+*co oc*co step on Cu-[cf2]N-5-cp is 050 EV, which is lower than 088 ev。The addition of PTFE reduced the Co adsorption energy on Cu(111)-[CF2]N-, effectively promoted the C-C coupling reaction, and further enhanced the reactivity of CO2 electroreduction to C2H4.
polymer modification strategy to modulate reaction microenvironment for enhanced co2 electroreduction to ethylene. angew. chem. int. ed.,, doi: 10.1002/anie.202313796.
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