Review and Outlook of Hydrogen Production through Catalytic Processes

Hydrogen holds immense potential as a sustainable energy source as a result of its eco-friendliness and high energy density. Thus, hydrogen can solve the energy and environmental challenges. However, it is crucial to produce hydrogen using sustainable approaches in a cost-efficient manner. Currently, hydrogen can be produced by utilizing diverse feedstocks, such as natural gas, methane, ammonia, smaller organic molecules (methanol, ethanol, glycerol, and formic acid), biomass, and water. These feedstocks undergo conversion into hydrogen through different catalytic processes, including steam reforming, pyrolysis, catalytic decomposition, gasification, electrolysis, and photo-assisted methods (photoelectrochemical, photocatalysis, and biophotolysis). Researchers have extensively explored various catalysts, including metals, alloys, oxides, non-oxides, carbon-based materials, and metal–organic frameworks, for these catalytic methods. The primary objectives have been to attain higher activity, selectivity, stability, and cost effectiveness in hydrogen generation. The efficacy of these catalytic processes is significantly dependent upon the performance of the catalysts, emphasizing the need for further research and development to create more efficient catalysts. However, during catalytic hydrogen production, gases like CO2, O2, CO, N2, etc. are produced alongside hydrogen. Separation techniques, such as pressure swing adsorption, metal hydride separation, and membrane separation, are employed to obtain high-purity hydrogen. Furthermore, a techno-economic analysis indicates that catalytic hydrogen production through steam reforming of natural gas/methane is currently viable and commercially successful. Photovoltaic electrolysis has been commercialized, but the cost of hydrogen production is still higher. Meanwhile, other photo-assisted methods are in the development phase and hold the potential for future commercialization.