Research Progress on Hydrogen and Carbon Materials Production from Methane Pyrolysis
The escalation of global warming and climate change necessitates the development of clean energy carriers. Hydrogen, with a high combustion value of 120 MJ/kg and net-zero carbon emissions, is a promising alternative. Catalytic methane pyrolysis offers a route to produce high-purity hydrogen and functional carbon materials simultaneously. However, challenges persist in catalyst deactivation due to carbon deposition and the efficient separation and valorization of carbon byproducts. This review systematically examines recent progress in solid and molten-medium catalysts for methane pyrolysis. It highlights strategies to enhance catalyst stability, including precise control of active sites, alloying, support optimization, and tuning the carbon-catalyst interface. The introduction of molten media catalytic systems, which feature dynamically refreshed gas-liquid interfaces, can fundamentally mitigate deactivation and facilitate continuous carbon separation. The paper discusses reaction mechanisms, catalytic performance, and control of carbon morphology, along with strategies for efficient separation and purification of carbon products in molten media. High-value applications of the produced carbon materials are also explored. The review underscores the potential of methane pyrolysis as a low-carbon technology for hydrogen production, while identifying key research directions for industrial scalability.