Serpentinization of olivine-rich ultramafic rocks is a fundamental geochemical process with significant implications for natural hydrogen (H₂) generation. This reaction, occurring in geological settings such as mid-ocean ridges and ophiolites, facilitates water-rock interactions that transform olivine into serpentine minerals while simultaneously producing molecular hydrogen. Given hydrogen’s role as a clean and renewable energy carrier, understanding the kinetics of serpentinization is crucial for optimizing its production. Various factors, including temperature, pressure, fluid salinity, and silica content, influence the reaction rate and hydrogen yield.
Building on previous research, this study employs controlled laboratory experiments to investigate olivine serpentinization kinetics, utilizing gas chromatography (GC) for real-time hydrogen measurement. A larger catalyst mass is used to enhance the representativeness of the reaction. To further refine our understanding, we incorporate small-scale characterization of hydrogen transport and thermo-poro-mechanical (TPM) effects using natural samples, which are systematically analyzed using SEM/EDS, XRD, XRF, and ICP-AES measurements before and after reaction experiments.
Experiments are conducted in batch (incubation) configurations under geologically relevant conditions (225℃-300°C) to evaluate hydrogen generation rates and the coupling between reaction kinetics and transport phenomena. Post-reaction characterization focuses on changes in the mineralogical evolution and the Fe(II)/Fe(III) ratio of these samples, enabling direct integration of these observations into kinetic modeling efforts.
By bridging small-scale experimental observations with macroscopic reservoir processes, this study advances our understanding of scalable, cost-effective hydrogen generation from geological sources. These findings contribute to the broader effort of harnessing geological hydrogen as a viable, low-carbon energy resource.