Scalable Electrosynthesis of Formamide through C−N Coupling at the Industrially Relevant Current Density of 120 mA cm⁻²

Abstract

The scalable and durable electrosynthesis of high-valued organonitrogen compounds from carbonand nitrogen-containing small molecules, especially operating at a high current density, is highly desirable. Here, a one-pot electrooxidation method to synthesize formamide (HCONH 2 ) from methanol and ammonia over a commercial boron-doped diamond (BDD) catalyst is reported. The formamide selectivity from methanol and formamide Faradaic efficiency (FE HCONH 2 ) achieve 73.2 % and 41.2 % at the current density of 120 mA cm À 2 with high durability. The CÀ N bond originates from the nucleophilic attack of ammonia on an aldehyde-like intermediate. Impressively, an 8 L electrolyzer is employed for the pilot plant test over a 2200 cm 2 BDD electrode, which exhibits 33.5 % FE HCONH 2 at 120 mA cm À 2 (current: 264 A) with a yield rate of 36.9 g h À 1 , demonstrating the potential of this technique for large-scale electrosynthesis of formamide.

Innovative Electrochemical Strategies for Hydrogen Production: From Electricity Input to Electricity Output

“…Duan and co‐workers reported an electrocatalytic C−C coupling strategy in a direct C(sp 3 )−H alkynylation of tertiary aliphatic amines with 1‐iodoalkynes over Au/NiFe‐LDH with H 2 production in a single electrochemical system [61] . Moreover, the synthesis of formamide by the electrooxidation of methanol and ammonia under ambient conditions through C−N coupling has been reported by Zhang and co‐workers [62] . Under optimized reaction conditions, high formamide selectivity (73.2 %) and a Faradaic efficiency of 41.2 % were achieved at 120 mA cm −2 .…”

Electrochemical C–N coupling of CO2and nitrogenous small molecules for the electrosynthesis of organonitrogen compounds

“…In another study, Zhang et al reported a strategy for the direct synthesis of formamide via the electrooxidation of CH 3 OH and NH 3 over a commercial boron-doped diamond (BDD) catalyst with a formamide FE of 41.2% at a high current density of 120 mA cm −2 . 222 Compared to the traditional high-temperature and high-pressure reaction conditions (Fig. 20a and b), renewable energy-driven electrosynthesis has attracted increasing interest for a carbon-neutral future.…”

Minireview of Coupled Electrochemical Hydrogen Production and Organic-Oxidation for Low Energy Consumption

“…A large current can be obtained both in C−C and C−N coupling strategies above, indicating electrochemical coupling strategies with HER should also be effective. 80…”