(543e) Electrochemical Nitrogen Reduction Reaction on Transition Metal Nitride Nanoparticles in Proton Exchange Membrane Electrolyzers
Transition metal nitride nanoparticles are synthesized and utilized as catalysts for electrochemical nitrogen reduction reaction (ENRR) to produce ammonia in a proton exchange membrane electrolyzer (PEMEL). The catalysts show an average ENRR rate and Faradaic efficiency (FE) of 3.3 Ã 10â10 mol sâ1 cmâ2 (6.6 Ã 10â10 mol sâ1 mgâ1) and 5.95% at â0.1 V within 1 h, respectively. Both the ENRR rate and FE are approximately two orders of magnitude higher than those of noble metal catalysts. Time-dependent results suggest that the catalytic activity of transition metal nitride nanoparticles is stable at â0.1 V, with the catalytic activity decreasing by only 28% during 4 h test. Ex situ X-ray photoelectron spectroscopy (XPS) and operando electrochemical and synchrotron-based X-ray absorption spectroscopic (XAS) analysis reveal that transition metal oxynitride is the active phase for nitrogen reduction.