Dielectric barrier discharge plasma-assisted catalytic ammonia synthesis: synergistic effect of Ni-MOF-74 catalyst and nanosecond pulsed plasma

Ammonia is one of the most important chemical raw materials in both manufacture and life of human. Traditionally Haber-Bosch method for ammonia synthesis involves high temperature and high pressure conditions, leading to significant energy consumption and environmental pollution. Non-thermal plasma (NTP) is a promising alternative approach to ammonia synthesis at low temperature and atmospheric pressure. In this study, the synergistic effect of nanosecond pulsed dielectric barrier discharge (np-DBD) and Ni-MOF-74 catalyst was investigated in ammonia synthesis by utilizing nitrogen and hydrogen as feedstock. The results demonstrated that the plasma catalytic-synthesis process parameters play a crucial role in the synthesis process of ammonia. The highest ammonia synthesis rate of 5145.16 μmol·g⁻¹·h⁻¹ with an energy efficiency of 1.27 g·kWh⁻¹ was observed in the presence of the Ni-MOF-74 catalyst, which was 3.7 times higher than that without Ni-MOF-74 catalyst. The synergistic effect of Ni-MOF-74 catalyst and nanosecond pulsed plasma was explored by in-situ plasma discharge diagnostics.