Influence of 50 Hz and 20 kHz Plasma Generator Frequency on Ammonia Decomposition for Hydrogen Recovery

The development of alternative energy is crucial to realizing the goals of the Paris Agreement. Hydrogen is a key energy carrier, and ammonia is considered its practical storage medium due to its high H2 content and efficient storage and transportation. However, efficient NH3 decomposition methods are needed to recover stored hydrogen. Plasma-assisted decomposition offers a potential solution, but high energy consumption, mainly due to inefficient power supply systems, remains a challenge. This study examines the impact of varying the driving frequency of a gliding discharge plasma system on ammonia decomposition, comparing low-frequency 50 Hz and high-frequency 20 kHz power supplies. Results show that high-frequency plasma enhances electron density and energy distribution, increasing the amount of vibrationally excited nitrogen molecules. This improves catalyst activation, leading to higher ammonia conversion and hydrogen production. Compared to the thyristor-powered system, the high-frequency system increased ammonia decomposition productivity by 30% and reduced energy consumption by 36% using a coprecipitated catalyst. These findings emphasize the importance of a plasma generator optimizing plasma-assisted ammonia decomposition and improving efficiency in hydrogen production.