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 vs. reversible hydrogen electrode, respectively, with good durability. Noticeably, a conversion rate of 86.9% is achieved after 10 h bulk electrolysis.