Electrochemical synthesis of ammonia over CuO/Zr0.9Sc0.1O2 nanofibers

Abstract

Ammonia is an alternative fuel for high-temperature fuel cells due to its high hydrogen content of 17.6 %, and electrochemical synthesis of ammonia from nitrogen-containing compounds is emerging as a prominent method as it is an environment-friendly and energy-saving process. In this study, CuO/Zr_0.9Sc_0.1O₂ nanofibers are proposed as a high-efficiency catalyst for ammonia production from nitrate reduction, which attains a high Faradaic efficiency (FE) of 84.56 % and a large ammonia yield of 32.98 mg h⁻¹ mg⁻¹_cat., and it also maintains an excellent performance in electrolyte with low nitrate concentrations. Meanwhile, it shows no degradation during electrolysis for nearly 100 h and the microstructure remains intact. Theoretical calculations reveal that the CuO/tZSO heterojunction enhances the electron transfer kinetics, which reduces the energy of the potential-determining step and significantly improves the activity. The findings are beneficial to design catalyst with a heterostructure for synthesis of green ammonia.