One-Pot Electrochemical Synthesis of (Hydroxyamino)methanesulfonate from CO ₂ , Nitrate/Nitrite, and Sulfite

Carbon–heteroatom (C–X, X = N, S, P, etc.) coupling represents a promising strategy to diversify the product scope of the electrocatalytic CO2 reduction reaction (eCO2RR). To date, most studies have focused on single C–X bond formation between CO2 and one heteroatom source in one electrochemical reaction. The formation of multiple C–X bonds in eCO2RR remains largely unexplored due to the inherent complexity of multicomponent and multistep reaction pathways. Herein, we report, for the first time, the formation of multiple C–X bonds in eCO2RR, where (hydroxyamino)methanesulfonate (HAMS), a compound containing both C–N and C–S bonds, is synthesized via electroreduction of CO2 in an electrolyte solution containing nitrate/nitrite (NO3–/NO2–) and sulfite (SO32–) using a cobalt phthalocyanine supported on the carbon nanotube (CoPc/CNT) catalyst. Mechanistic studies and theoretical calculations reveal that the formation of HAMS proceeds via C–N coupling followed by C–S bond formation. By adjusting the electrolyte composition, the maximum faradaic efficiency of 5.8% and the highest partial current density of −2.4 mA cm–2 were achieved for HAMS. This work demonstrates a rare one-pot electrosynthesis of products with multiple C–X bonds (i.e., involving both C–N and C–S coupling) and provides a new route toward constructing functionally complex molecules from simple, abundant precursors.