Thermal Decomposition Pathways for Hydrogen Production: Selection and Efficiency Enhancement

Abstract

The dual-carbon target has driven the low-carbon transformation of hydrogen energy. Thermal decomposition for hydrogen production, which can be coupled with high-temperature heat sources such as solar energy, nuclear energy, and industrial waste heat, has emerged as an important direction for green hydrogen production. This paper systematically reviews four core pathways: direct hydrothermal decomposition of water, pyrolysis of hydrocarbons, ammonia thermal decomposition, and thermochemical cycle water splitting. It compares their reaction mechanisms, process conditions, technical advantages and disadvantages, as well as applicable scenarios. Direct hydrothermal decomposition uses clean raw materials but requires ultra-high temperatures and remains at the fundamental research stage. Hydrocarbon pyrolysis technology is mature and serves as a transitional solution for the shift from fossil energy to hydrogen energy. Ammonia thermal decomposition features mild reaction conditions and is well-suited for distributed hydrogen supply scenarios. Thermochemical cycle water splitting reduces the required reaction temperature and represents the core technology for future large-scale zero-carbon hydrogen production. The study indicates that pathway selection must comprehensively consider factors including raw materials, heat sources, carbon emissions, application scenarios, and economic viability. In the future, thermal decomposition for hydrogen production will develop toward low-temperature and high-efficiency processes, coupling with clean energy sources, and system integration. These advancements will provide strong support for the industrialization of hydrogen energy and the low-carbon transformation of the energy sector.