Three-dimensional porous Co foam with nanosheets subunits for high-performance electrocatalytic nitrate-to-ammonia conversion

Abstract

Electrochemical nitrate (NO₃⁻) reduction is a “turn waste into treasure” strategy that removes NO₃⁻ pollutants and simultaneously converts them into economically valuable ammonia (NH₃), but this process requires highly active and selective catalysts. Herein, three-dimensional porous Co foam with nanosheet subunits supported on a Ti plate (Co foam/TP) constructed by hydrogen bubble template assisted electrodeposition is reported as a high-performance catalyst to drive the electrochemical NO₃⁻-to-NH₃ conversion. Such Co foam/TP exhibits an exceptional electrocatalytic performance showing a maximum NH₃ faradaic efficiency of 96.5% with a corresponding NH₃ yield of up to 600.6 μmol h⁻¹ cm⁻² at −0.4 V. Additionally, a Zn–NO₃⁻ battery adopting Co foam/TP as the cathode delivers a peak power density of 6.8 mW cm⁻² and a satisfactory NH₃ yield of 111.0 μmol h⁻¹ cm⁻².