Solar-driven methanol steam reforming for low carbon and efficient hydrogen production: A review

Methanol, as a liquid organic hydrogen carrier, exhibits advantageous features such as easy storage, transportability, and low energy consumption at ambient conditions, making it a reliable on-site emergency hydrogen source. The adoption of steam reforming allows for the efficient release of hydrogen from liquid organic hydrogen carriers, thus offering a promising solution to hydrogen storage and transport challenges. Moreover, leveraging renewable energy sources (solar energy) to replace conventional fossil fuels for powering methanol steam reforming (MSR) reactions enables the utilization of high-quality on-demand hydrogen sources with reduced carbon emissions. However, several challenges in solar-driven MSR research persist, encompassing catalyst lifespan, reaction rate, reaction stability, and environmental impact. This review comprehensively summarizes and discusses recent advancements in solar-driven MSR, focusing on solar reactor design, development of control strategies for reaction systems, investigation of energy storage systems for reactors, as well as analysis of the photothermal coupling reaction mechanism. The primary aim is to share the latest progress in solar-driven MSR and identify common challenges and future research directions. Specifically, this paper focuses on the development of a joint active/passive control system, the establishment of a complementary energy supply system with multiple drive modes, the development of a low-temperature and high-efficiency conversion technology for the reactants, and the exploration of a synergistic gain mechanism for the coupling of photothermal energy in MSR reactions. Furthermore, it advocates for interdisciplinary design approaches to achieve seamless integration between solar energy supply systems and MSR reaction systems, thereby minimizing energy losses during the reaction process. The insights provided in this review offer novel perspectives and directions for the development of low-carbon hydrogen production processes.