Potassium ions promote electrochemical nitrogen reduction on nano-Au catalysts triggered by bifunctional boron supramolecular assembly

The electrochemical way of reducing nitrogen to ammonia presents green and economic advantages to dial down irreversible damage caused by the energy-intensive Haber-Bosch process. Here, we introduce an advanced catalyst CB[7]-K2[B12H12]@Au with highly dispersed and ultrafine nano-gold. The CB[7]-K2[B12H12]@Au electrochemically driven ammonia yield and Faraday efficiency is as high as 41.69 μg h-1 mgcat.-1 and 29.53% (at -0.4 V vs. RHE), respectively, reaching the US Department of Energy (DOE) utility index of ambient ammonia production along with excellent cycle stability and tolerance that indicates a high potential of industrial practical value. Experimental results and theoretical calculations show that the key to an excellent electrochemical nitrogen reduction performance lies in the smart design of the CB[7]-K2[B12H12]@Au catalyst combining the stable substrate anchored Au nanoparticles and K+ ions that effectively prevent the hydrogen evolution reaction and polarize ∗N2 leading to lowering of the rate determining step. This research will promote the further development of electrochemical ammonia production with low environmental impact.