Efficient carboxylation of styrene and carbon dioxide by single-atomic copper electrocatalyst

Abstract

Electrocarboxylation of olefins with carbon dioxide (CO₂) is a potential approach to produce carboxylates as synthetic intermediates of polymer and pharmaceuticals. Nonetheless, due to the intrinsic inertness of CO₂ at ambient conditions, the electrocarboxylation efficiency has been quite limited, typically with high applied potentials and low current densities. In this work, we demonstrate that nitrogen-coordinated single-atomic copper sites on carbon framework (Cu/NC) served as an excellent electrocatalyst for electrocarboxylation of styrene with CO₂. The Cu/NC catalyst allowed to efficiently activate CO₂, followed by nucleophilic attack to carboxylate styrene to produce phenylsuccinic acid, thus leading the reaction toward the CO₂ activation pathway. The enhanced CO₂ activation capability enabled increased selectivity and activity for electrocarboxylation of styrene. The Faradaic efficiency of electrocarboxylation was 92%, suggesting most of the activated CO₂ proceeded to react with styrene rather than direct reduction to CO or CH₄. The electrocarboxylation exhibited almost 100% product selectivity toward phenylsuccinic acid, with a high partial current density of 58 mA·cm^-2 at -2.2 V (vs. Ag/AgI), corresponding to an outstanding production rate of 216 mg·cm^-2·h^-1, substantially exceeding previously reported works. Our work suggests an exciting perspective in electrocarboxylation of olefins by rational design of CO₂ activation electrocatalysts.

Keywords: CO(2); CO(2) reduction; Electrochemical carboxylation; Single-atomic Cu catalyst; Styrene.