Regulating the local microenvironment on porous Cu nanosheets for enhancing electrocatalytic CO₂ reduction selectivity to ethylene

Local microenvironments of the ECO2RR play an important role in tuning the adsorption energy of crucial intermediates, which helps enhance ECO2RR selectivity. Different types of organic polymers were used in this work to modify porous Cu NSs to regulate the local microenvironment and enhance the selectivity of the ECO2RR to C2H4. It is found that when porous Cu NSs are modified with anionic polystyrene vinylbenzyl methylimidazolium chloride (PSMIM), the selectivity of C2H4 reaches (62.34 +/- 1.48)%, while the selectivity of C2H4 on the cationic perfluorosulfonic acid polymer Nafion-modified electrode is only (25.41 +/- 1.80)%. CO-DRIFTS, in situ ATR-SEIRAS, and molecular dynamics simulation prove that the presence of PSMIM facilitates the adsorption of CO gas and *CO intermediates on the electrode. High *CO coverage is advantageous for the dimerization of *CO, leading to an enhanced selectivity of C2H4. Developing PSMIM-Cu NS electrodes is expected to further accelerate the practical application of porous Cu NSs for the ECO2RR to produce C2H4.