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

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.