The green and sustainable electrocatalytic conversion of nitrogen-containing compounds to ammonia is currently in high demand in order to replace the eco-unfriendly Haber–Bosch process. Model catalysts for the nitrate reduction reaction were obtained by electrodeposition of metal Co, Fe, and bimetallic Fe/Co nanoparticles from aqueous solutions onto a graphite substrate. The samples were characterized by the following methods: SEM, XRD, XPS, UV–vis spectroscopy, cyclic (and linear) voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. In addition, the determination of the electrochemically active surface was also performed for all electrocatalysts. The best electrocatalyst was a sample containing Fe-nanoparticles on the layer of Co-nanoparticles, which showed a Faradaic efficiency of 58.2% (E = −0.785 V vs. RHE) at an ammonia yield rate of 14.6 μmol h⁻¹ cm⁻² (at ambient condition). An opinion was expressed to elucidate the mechanism of coordinated electrocatalytic action of a bimetallic electrocatalyst. This work can serve primarily as a starting point for future investigations on electrocatalytic conversion reactions to ammonia using model catalysts of the proposed type.

A sustainable reaction of electrocatalytic nitrate conversion in ammonia production (NO₃RR) occurring under ambient conditions is currently of prime interest, as well as urgent research due to the real potential replacement of the environmentally unfavorable Haber–Bosch process. Herein, a series of electrocatalysts based on two-component cobalt alloys was synthesized using low-cost non-noble metals Co, Fe, Cr, and also Si. The samples of electrocatalysts were characterized and studied by the following methods: SEM, EDX, XRD (both transmission and reflection), UV–VIS spectroscopy, optical microscopy, linear (and cyclic) voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Beyond that, the determination of electrochemically active surface area was also carried out for all samples of electrocatalysts. Unexpectedly, the sample having an intermetallic compound (IMC) of the composition Co₂Si turned out to be the most highly effective. The highest Faradaic efficiency (FE) of 80.8% at E = −0.585 V (RHE) and an ammonia yield rate of 22.3 µmol h⁻¹ cm⁻² at E = −0.685 V (RHE) indicate the progressive role of IMC as the main active component of the electrocatalyst. Thus, this study demonstrates the promise and enormous potential of IMC as the main component of highly efficient electrocatalysts for NO₃RR. This work can serve primarily as a starting point for future studies of electrocatalytic conversion reactions in the production of ammonia using IMC catalysts containing non-noble metals.

Green and sustainable electrocatalytic conversion of nitrogen-containing compounds to ammonia are currently in high demand in order to replace the eco-unfriendly Haber-Bosch process. Model catalysts for the nitrate reduction reaction were obtained by electrodeposition of metal Co, Fe and bimetallic Fe/Co nanoparticles from aqueous solutions onto a graphite substrate. The samples were characterized by the following methods: SEM, XRD, XPS, UV-vis spectroscopy, cyclic (and linear) voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Besides, the determination of electrochemically active surface was also performed for all electrocatalysts. The best electrocatalyst was a sample containing Fe-nanoparticles on the layer of Co-nanoparticles, which showed the Faradaic efficiency 58.2% (E=-0.785 V vs. RHE) at the ammonia yield rate of 14.6 μmol h-1 cm-2. An opinion was expressed on elucidation of the mechanism of coordinated electrocatalytic action of a bimetallic electrocatalyst. This work can serve primarily as a starting point for future investigations on electrocatalytic conversion reactions to ammonia using model catalysts of the proposed type.

A sustainable reaction of electrocatalytic nitrate conversion in ammonia production (NO3RR) occurring under ambient conditions is currently of prime interest, as well as urgent research due to the real potential replacement of the environmentally unfavorable Haber-Bosch process. Herein, a series of electrocatalysts based on two-component cobalt alloys was synthesized using low-cost non-noble metals Co, Fe, Cr and also Si. The samples of electrocatalysts were characterized and studied by the following methods: SEM, EDX, XRD (both transmission and reflection), UV-vis spectroscopy, optical microscopy, linear (and cyclic) voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Beyond that, the determination of electrochemically active surface area was also carried out for all samples of electrocatalysts. Unexpectedly, the sample having an intermetallic compound (IMC) of the composition Co2Si turned out to be the most highly effective. The highest Faradaic efficiency (FE) of 80.8% at E = -0.585 V (RHE) and an ammonia yield rate of 22.3 µmol h-1 cm 2 at E = 0.685 V (RHE) indicate the progressive role of IMC as the main active component of the electrocatalyst. Thus, this study demonstrates the promise and enormous potential of IMC as the main component of highly efficient electrocatalysts for NO3RR. This work can serve primarily as a starting point for future studies of electrocatalytic conversion reactions in the production of ammonia using IMC catalysts containing non-noble metals.