Achieving Synchronization of Electrochemical Production of Ammonia from Nitrate and Ammonia Capture by Constructing a “Two‐In‐One” Flow Cell Electrolyzer

Abstract

AbstractThe electrochemical nitrate reduction reaction (NO3−RR) provides a promising route to produce ammonia (NH3) while addressing environmental issues of NO3−. Although great success has been achieved on the development of efficient NO3−RR electrocatalysts, few has concerned about how to capture NH3from the electrolyte, despite that the production and capture of NH3are equally important to the practical application of NO3−RR. Here, inspired by the fact that nearly all in situ generated NH3is gaseous at the electrode surface during the small‐current NO3−RR, a “two‐in‐one” flow cell electrolyzer is smartly designed that integrates the chambers of NO3−RR electrolysis and NH3capture through a commercial gas diffusion electrode, aiming at achieving the synchronization of NH3production and capture. Remarkably, this electrolyzer also enables rapid transport of NH3products away from the three‐phase reaction interfaces, thereby significantly promoting the conversion of NO3−to NH3. By using robust electrocatalysts with the function like nanoreactors, the electrolyzer delivers a maximum ammonia Faradaic efficiency of 90.2%, along with a large current density (−528.0 mA cm−2) and NH3capture rate of 90.4%. Clearly, this work provides opportunities to concurrently produce and capture NH3and thus help the realization of nitrogen cycle.