Synergistic bimetallic CoFe2O4 clusters supported on graphene for ambient electrocatalytic reduction of nitrogen to ammonia

The energy-intensive nature, high level of CO2 emission and sophisticated infrastructure requirement hampered the utilization of the Haber-Bosch process as a green and decentralized system for NH3 production. The electrochemical N-2 reduction reaction (NRR) provides a promising alternative to fix N-2 under ambient conditions. Here, we report CoFe2O4 nanoclusters anchored on reduced graphene oxide for enhanced nitrogen reduction. In contrast to monometallic counterparts, this composite catalyst achieves a faradaic efficiency of 6.2% with a high rate of NH3 production of 4.2 x 10(-11) mol s(-1) cm(-2) in 0.1 M Na2SO4 aqueous electrolyte. Amelioration of NRR performance could be attributed to the availability of different types of adsorption and active sites for N-2 after the incorporation of Co in the Fe3O4 structure. Also, the homogeneous dispersion of nanoclusters on a 2D support can achieve higher active site density. This work provides a new category of binary metal oxides catalysts for NRR under ambient conditions.