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

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 & mu;mol 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 & mu;mol h(-1) cm(-2).