High-efficiency nitrate electroreduction to ammonia on electrodeposited cobalt–phosphorus alloy film

Abstract

Electrocatalytic eight-electron nitrate (NO₃^-) reduction is a sustainable strategy to degrade NO₃^- and convert it into high value-added ammonia (NH₃) but needs efficient catalysts with high activity and selectivity. Our study shows the use of Ti plate supported cobalt-phosphorus alloy film (Co-P/TP) as a highly active and selective electrocatalyst for ambient NO₃^--to-NH₃ conversion. In 0.2 M Na₂SO₄ with 200 ppm NO₃^-, Co-P/TP offers an NH₃ yield rate of 416.0 ± 7.2 μg h^-1 cm^-2 and a high faradaic efficiency of 93.6 ± 3.3% at -0.6 V and -0.3 V <i>vs.</i> reversible hydrogen electrode, respectively, with good durability. Noticeably, a conversion rate of 86.9% is achieved after 10 h bulk electrolysis.