Bioinspired Electrocatalyst for Electrochemical Reduction of N2 to NH3 in Ambient Conditions.

Abstract

Industrial ammonia production depends heavily on the traditional Haber-Bosch method at the expense of CO2 emissions and large energy consumptions. Artificial fixation of nitrogen to ammonia is therefore regarded as a promising path to yield ammonia in energy-saving conditions. However, a competent electrocatalyst is highly desired, owing to the extremely stable bond of N≡N. In this work, we report Fe2(MoO4)3 nanoparticles as a non-noble-metal electrocatalyst, inspired by nitrogenase enzymes for electrochemically converting nitrogen into ammonia, which achieves a Faradic efficiency of 9.1% and an excellent NH3 yield of 18.16 μg h-1 mg-1 cat in 0.1M sodium sulfate at -0.6 V vs reversible hydrogen electrode. Also, it has a better ammonia yield rate of 20.09 μg h-1 mg-1 cat in 0.1 M hydrochloric acid. Moreover, this noble-metal-free catalyst exhibits a unique reaction process selectivity and stability compared with the other catalysts working in harsh conditions. The specific reaction processes are analyzed by density functional theoretical calculations to gain insights into the nitrogen reduction reaction (NRR) by this catalyst.