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

The scalable and durable electrosynthesis of high-valued organonitrogen compounds from carbon- and 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 ${{_{{\rm HCONH}{_{2}}}}}$ ) achieve 73.2 % and 41.2 % at the current density of 120 mA cm -2 with high durability. The C-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 ${{_{{\rm HCONH}{_{2}}}}}$ at 120 mA cm -2 (current: 264 A) with a yield rate of 36.9 g h -1 , demonstrating the potential of this technique for large-scale electrosynthesis of formamide.