One-Pot Electrochemical Synthesis of (Hydroxyamino)methanesulfonate from CO2, 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.