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

Abstract The electrochemical nitrate reduction reaction (NO 3 − RR) provides a promising route to produce ammonia (NH 3 ) while addressing environmental issues of NO 3 − . Although great success has been achieved on the development of efficient NO 3 − RR electrocatalysts, few has concerned about how to capture NH 3 from the electrolyte, despite that the production and capture of NH 3 are equally important to the practical application of NO 3 − RR. Here, inspired by the fact that nearly all in situ generated NH 3 is gaseous at the electrode surface during the small‐current NO 3 − RR, a “two‐in‐one” flow cell electrolyzer is smartly designed that integrates the chambers of NO 3 − RR electrolysis and NH 3 capture through a commercial gas diffusion electrode, aiming at achieving the synchronization of NH 3 production and capture. Remarkably, this electrolyzer also enables rapid transport of NH 3 products away from the three‐phase reaction interfaces, thereby significantly promoting the conversion of NO 3 − to NH 3 . 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 NH 3 capture rate of 90.4%. Clearly, this work provides opportunities to concurrently produce and capture NH 3 and thus help the realization of nitrogen cycle.