A comprehensive review on recent breakthroughs in hydrogen production from hydrogen sulfide decomposition: Harnessing the power of plasma

With escalating energy demands, the quest for clean and sustainable energy solutions is intensifying. H2 serves as a clean energy source and plays a crucial role in numerous industrial processes. The global interest in the hydrogen (H2) economy is burgeoning, emphasizing the importance of H2 production and utilization. Various methods are being explored for H2 production, encompassing both fossil-based and renewable sources worldwide. Hydrogen sulfide (H2S) which is an off-gas in refineries and anaerobic processes can be decomposed to produce pure H2 and sulfur. H2S emitted from industrial processes and anaerobic decomposition of organic matter as is a significant environmental concern due to its corrosive and toxic nature. Numerous techniques, including thermal, thermo-catalytic, and electrocatalytic approaches, are employed for H2S decomposition. The plasma-catalytic route has emerged as a promising technology in recent years but remains at lower technology readiness level. Factors influencing the effectiveness of H2S decomposition through plasma catalysis include feed composition, flow rate, reaction kinetics and reactor design, electrode types, plasma generator, retention time, and catalyst. This article reviews the different routes of H2 production with focus on H2S decomposition to H2, comparative analysis of various H2S decomposition methods with detailed review of plasma based H2S decomposition. It delves into the characteristics of different plasma sources, comparing their performance alongside various process parameters and catalysts. Additionally, the paper explores the potential and feasibility of large-scale application of plasma catalysis for H2 production. It has been found through the analysis that hydrogen production can vary from 20 % to 98 % for different methods. With the selection of a suitable process and optimization of process parameters, above 90 % H2S conversion and equivalent hydrogen can be achieved. Among these, the literature suggests that the plasma-catalysis process currently at TRL 6 exhibited above 95 % conversion along with several energy and environmental benefits, demanding large-scale studies in the future.