Iron Nanoparticles on Porous Carbon Discs: Electrocatalysts with Over 30% Energy Efficiencies for the Production of Ammonia from Nitrate.

Disc-shaped precursor materials (Fe-HBD) are prepared by the complexation of iron with 2,5-dihydroxy-1,4-benzoquinone. Through the carbonization of Fe-HBD at 700 °C, Fe nanoparticles on carbon disc matrixes (CD@Fe-700) are synthesized. The CD@Fe-700 with a high surface area of 424 m2 g-1 and micro/mesoporosity showed promising electrocatalytic performance in the nitrate reduction reaction (NO3RR) to ammonia with ammonia yield rates of 1.8-13.5 mg h-1 cm-2 at overpotentials of -0.2--0.6 V (vs. RHE), reaching energy efficiencies up to 32.6-34.7%.