Accelerating the Activation of NOx- on Ru Nanoparticles for Ammonia Production by Tuning Their Electron Deficiency

Abstract

Stable and portable ammonia (NH3) is a promising, low-cost, and environment-friendly medium for energy storage. How to achieve the rapid production of NH3 from reducing NOx- in aqueous systems and industrial wastewater via electrochemical methods remains the main challenge for practical application on a large scale. The corresponding electrocatalysts as the key materials in electrochemical devices suffer from low activity, especially in neutral systems. In this work, we successfully elevated the activity of the bench-mark Ru electrocatalysts to more than 30 times via construction of rectifying contact of Ru metals and noble carbons. We theoretically predicted and then rationally designed a new type of P-O rich carbon with large work functions as "noble" supports to attract a pronounced number of electrons from Ru metals at the rectifying interface. The resulting electron deficiency of Ru metals largely promotes the pre-adsorption and activation of NOx- anions, providing high Faradaic efficiencies (>96%) and record-high turnover frequency values for universal NO2- and NO3- reduction in neutral solution.