Combining Fe nanoparticles and pyrrole-type Fe-N sites on less-oxygenated carbon supports for electrochemical CO reduction.

A great challenge for electrochemical CO reduction is to improve energy efficiency, which requires reducing overpotential while increasing product Faraday efficiency. Here, we designedly synthesize a hybrid electrocatalyst consisting of Fe nanoparticles, pyrrole-type Fe-N sites and less-oxygenated carbon supports, which exhibits a remarkable CO Faraday efficiency above 99% at an ultralow overpotential of 21 mV, reaching the highest cathode energy efficiency of 97.1% to date.