Renewable energy driven electroreduction nitrate to ammonia and in-situ ammonia recovery via a flow-through coupled device.

• Cl modified Cu foam electrode was used to efficiently reduce nitrate. • The O–H···Cl hydrogen-bonds accelerated water dissociation to generate atomic H*. • A novel device was designed for nitrate conversion and in-situ ammonia recovery. • A stable NH 3 yield rate of 420 μg h−1 cm−2 could be achieved over 100 h. Green ammonia production from wastewater via electrochemical nitrate reduction contributes substantially to the realization of carbon neutrality. Nonetheless, the current electrochemical technology is largely limited by the lack of suitable device for efficient and continuous electroreduction nitrate into ammonia and in-situ ammonia recovery. Here, we report a flow-through coupled device composed of a compact electrocatalytic cell for efficient nitrate reduction and a unit to separate the produced ammonia without any pH adjustment and additional energy-input from the circulating nitrate-containing wastewater. Using an efficient and selective Cl-modified Cu foam electrode, nearly 100% NO 3 − electroreduction efficiency and over 82.5% NH 3 Faradaic efficiency was realized for a wide range of nitrate-containing wastewater from 50 to 200 mg NO 3 −-N L−1. Moreover, this flow-through coupled device can continuingly operate at a large current of 800 mA over 100 h with a sustained NH 3 yield rate of 420 μg h−1 cm−2 for nitrate-containing wastewater treatment (50 mg NO 3 −-N L−1). When driven by solar energy, the flow-through coupled device can also exhibit exceptional real wastewater treatment performance, delivering great potential for practical application. This work paves a new avenue for clean energy production and environmental sustainability as well as carbon neutrality. [Display omitted] [ABSTRACT FROM AUTHOR]