From methane to hydrogen: A comprehensive review to assess the efficiency and potential of turquoise hydrogen technologies

Hydrocarbons are important for many countries' economy and represent a major part of the energy supply chain, at least in the foreseeable future. The proven oil and gas reserves globally represent a formidable energy resource that could meet the world's current energy demand for approximately 100 years. As the world shifts to a low carbon future, the market for oil and gas will be affected. Hence, the development of approaches and technologies to valorize these hydrocarbons, while reducing the impact on the environmental will be required. One such approach is to extract hydrogen (H₂) from hydrocarbons while capturing and using or storing carbon dioxide (CO₂). Another near-term economical solution that paves the way for scalable hydrogen infrastructure is methane (CH₄) pyrolysis, also called thermal methane cracking, methane decomposition or turquoise hydrogen. This comprehensive review examines the state-of-the-art in methane pyrolysis for hydrogen production and valuable solid carbon, highlighting the method's potential and addressing the persistent challenges that impede its commercialization. The study evaluates various approaches, including solid catalysts, molten mediums, and plasma-assisted methods. The limitations and drawbacks of each technique are discussed. The synergy between the hydrogen and carbon industries is highlighted, emphasizing the need for collaborative efforts to unlock the full potential of methane pyrolysis. In addition to evaluating existing challenges, the review provides strategic recommendations for overcoming hurdles, including innovations in catalyst design, optimization of molten media, and industry partnerships. It also emphasizes the importance of policy engagement, comprehensive cost and lifecycle analysis, and technological innovations to propel methane pyrolysis toward commercial success. The comprehensive assessment presented in this review aims to guide future research directions, foster collaboration between academia and industry, and contribute to the development of a sustainable and economically viable methane pyrolysis process for hydrogen production and valuable solid carbon.