Non-thermal plasma assisted catalytic nitrogen fixation with methane at ambient conditions

Abstract

Sustainable and economical nitrogen (N2) fixation could offset the significant environmental and societal costs associated with the energy-intensive Haber-Bosch process. Yet, limited progress from these routes has been made to-date given unresolved low ammonia yield and complicated reaction pathways. The threshold efficiency required for a non-thermal plasma (NTP) process to become competitive is established for various scenarios of hydrogen sources with CO2-free renewable energy. Herein, we report a novel non-thermal plasma driven N2 fixation pathway with methane (CH4) over a low-cost Cu/SiO2 catalyst to form a high ammonia yield of almost 7% as well as value-added hydrogen, gaseous and liquid hydrocarbons as byproducts. The presence of CH4 promoted the N2 fixation degree by up to 17%. Both experimental and computational work performed in this study reveals that plasma driven CH4 and N2 activation induced the formation of highly energetic electrons in the plasma regime and the thereafter produced active species reacted on the copper nanoparticle surface dispersed on the outer surface of the silica support, securing good catalytic activity and stability. A coincidence between theoretical simulation and experimental data provides significant insights into rational design of charged catalyst for facilitating non-thermal plasma assisted N2 fixation with natural gas directly and unfold novel avenues for sustainable technology development through potential renewability and zero-carbon emission approach.