Microtubular Gas Diffusion Electrode Based on Ruthenium-Carbon Nanotubes for Ambient Electrochemical Nitrogen Reduction to Ammonia

Abstract

The drawback of the energy-intensive Haber-Bosch process promotes the research and development of alternative ammonia (NH3) synthesis approaches. The electrochemical nitrogen (N2) reduction reaction (eNRR) may offer a promising method to produce NH3 independent of fossil-fuel-based hydrogen production. However, the low solubility and the low-efficiency mass transport of N2 in aqueous electrolytes are still among the challenges facing the feasibility of eNRR. Herein, we demonstrate a microtubular ruthenium-carbon nanotube gas diffusion electrode (Ru−CNT GDE), for the first time, applying it to electrochemical NH3 synthesis in an H-type cell under ambient conditions. The highest reported Ru-catalyzed NH3 yield rate of 2.1×10−9 mol/cm2 s and high faradaic efficiency of 13.5 % were achieved, showing the superior effect of Ru−CNT GDEs on the eNRR performance. This work provides a new approach for the design and fabrication of self-standing catalyst-loaded GDEs for eNRR.