Electrochemical Upgrading of Formic Acid to Formamide via Coupling Nitrite Co-Reduction
Chengying Guo, Wei Zhou, Xianen Lan, Yuting Wang, Tieliang Li, Shuhe Han, Yifu Yu, Bin Zhang
Abstract
Formic acid (HCOOH) can be exclusively prepared through CO2 electroreduction at an industrial current density (0.5 A cm–2). However, the global annual demand for formic acid is only ∼1 million tons, far less than the current CO2 emission scale. The exploration of an economical and green approach to upgrading CO2-derived formic acid is significant. Here, we report an electrochemical process to convert formic acid and nitrite into high-valued formamide over a copper catalyst under ambient conditions, which offers the selectivity from formic acid to formamide up to 90.0%. Isotope-labeled in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy and quasi in situ electron paramagnetic resonance results reveal the key C–N bond formation through coupling *CHO and *NH2 intermediates. This work offers an electrochemical strategy to upgrade CO2-derived formic acid into high-value formamide.