Kinetic Study for Plasma Assisted Cracking of NH 3 : Approaches and Challenges.

Ammonia is considered as one of the promising hydrogen carriers toward a sustainable world. Plasma assisted decomposition of NH 3 could provide cost- and energy-effective, low-temperature, on-demand (partial) cracking of NH 3 into H 2 . Here, we presented a temperature-dependent plasma-chemical kinetic study to investigate the role of both electron-induced reactions and thermally induced reactions on the decomposition of NH 3 . We employed a plasma-chemical kinetic model (KAUSTKin), developed a plasma-chemical reaction mechanism for the numerical analysis, and introduced a temperature-controlled dielectric barrier discharge reactor for the experimental investigation using 1 mol % NH 3 diluted in N 2 . As a result, we observed the plasma significantly lowered the cracking temperature and found that the plasma-chemical mechanism should be further improved to better predict the experiment. The commonly used rates for the key NH 3 pyrolysis reaction (NH 3 + M ↔ NH 2 + H + M) significantly overpredicted the recombination rate at temperatures below 600 K. Furthermore, the other identified shortcomings in the available data are (i) thermal hydrazine chemistry, (ii) electron-scattering cross-section data of N x H y , (iii) electron-impact dissociation of N 2 , and (iv) dissociative quenching of excited states of N 2 . We believe that the present study will spark fundamental interest to address these shortcomings and contribute to technical advancements in plasma assisted NH 3 cracking technology.