A Bifunctional Catalyst for Green Ammonia Synthesis from Ubiquitous Air and Water

Abstract Ammonia (NH 3 ) is essential for modern agriculture and industry, and, due to its high hydrogen density and no carbon emission, it is also expected to be the next‐generation of “clean” energy carrier. Herein, directly from air and water, a plasma‐electrocatalytic reaction system for NH 3 production, which combines two steps of plasma‐air‐to‐NO x − and electrochemical NO x − reduction reaction (eNO x RR) with a bifunctional catalyst, is successfully established. Especially, the bifunctional catalyst of CuCo 2 O 4 /Ni can simultaneously promote plasma‐air‐to‐NO x − and eNO x RR processes. The easy adsorption and activation of O 2 by CuCo 2 O 4 /Ni greatly improve the NO x − production rate at the first step. Further, CuCo 2 O 4 /Ni can also resolve the overbonding of the key intermediate of * NO, and thus reduce the energy barrier of the second step of eNO x RR. Finally, the “green” NH 3 production achieves excellent FE NH3 (96.8%) and record‐high NH 3 yield rate of 145.8 mg h −1 cm −2 with large partial current density (1384.7 mA cm −2 ). Moreover, an enlarged self‐made H‐type electrolyzer improves the NH 3 yield to 3.6 g h −1 , and the obtained NH 3 is then rapidly converted to a solid of magnesium ammonium phosphate hexahydrate, which favors the easy storage and transportation of NH 3 .