Role of Ethylene Diamine Tetraacetate as an Additive in Electrolyte on Intermediate Stabilization in Electrochemical CO 2 Reduction

Abstract Although an electrochemical CO 2 reduction reaction (ECO 2 RR) can provide an ideal route to produce CH 4 , its selectivity is significantly hindered due to kinetically complex steps. To improve CH 4 selectivity, this study focuses on microenvironmental engineering using an additive of ethylene diamine tetraacetate (EDTA) in electrolyte. EDTA interacts with the Cu catalyst, altering its electronic structure and promoting CO 2 activation, in addition, it forms additional hydrogen bonding with key intermediates of *CO and *CHO leading to their stabilization. These phenomena were experimentally and theoretically demonstrated as exhibiting the facilitated CO 2 adsorption and the *CO to *CHO conversion with suppressing *CO desorption. As a result, Cu‐loaded N‐doped Carbon (Cu/N : C) with EDTA additive in electrolyte shows a significantly enhanced CH 4 selectivity, reaching a faradaic efficiency (FE) of 48 % and a partial current density ( J CH4 ) of 15.0 mA cm −2 at −1.8 V RHE . This performance surpasses that of pristine Cu/N : C, which exhibited marginal FE and J CH4 values of 32 %, and 6.8 mA cm −2 , respectively. It obviously emphasizes the importance of intermediate stabilization via microenvironmental engineering for selective CH 4 production. This approach provides great insight into developing an effective ECO 2 RR system for promoting CO 2 to value‐added chemicals and fuel conversion.