Pulse-Driven Paired Electrosynthesis of Formamide via Redox-Tuned Intermediate Management

Renewable electricity-driven electrocatalytic systems hold promise for the sustainable formamide (HCONH2) synthesis. However, a major bottleneck remains the low Faradaic efficiency (FE) and overall electron utilization inherent to current unipolar C-N coupling strategies, where substantial electron consumption at the counter electrode severely limits system efficiency. Here, we propose a redox-tuned paradigm (Ared+ Boxi→ C) through a pulsed paired electrosynthesis strategy. Using an atomically ordered CuPd catalyst with CH3OH and NO2- as feedstocks in an undivided cell, HCONH2 is simultaneously produced at both electrodes under optimized pulse conditions with alternating change in potential periodically (Ea = 1.3 V, ta = 10 s; Ec = -0.7 V, tc = 10 s). This system achieves an FE of 85.6% for HCONH2 at a current density of 81.5 mA cm-2, with a yield of 263.3 μmol·h-1·cm-2. The FE is higher than those reported to date. Mechanism studies reveal that pulsed operation creates a periodically switching cathode/anode environment. This enables the ordered CuPd catalyst to function sequentially as a reduction site (converting NO2- to *NH3) during cathodic pulses and as a co-oxidation site (converting *NH3 to *NH2 along with CH3OH to *HCOH) during anodic pulses, thereby driving efficient C-N bond coupling to form HCONH2. Techno-economic analysis further confirmed the significant industrial potential of this strategy in the future renewable energy market.