2018 AIChE Annual Meeting

(543e) Electrochemical Nitrogen Reduction Reaction on Transition Metal Nitride Nanoparticles in Proton Exchange Membrane Electrolyzers

Authors

Yang, X. - Presenter, University of Delaware
Nash, J., University of Delaware
Anibal, J., University of Delaware
Dunwell, M., University of Delaware
Yan, Y., University of Delaware
Xu, B., University of Delaware
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 × 10−10 mol s−1 cm−2 (6.6 × 10−10 mol s−1 mg−1) and 5.95% at −0.1 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 −0.1 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.