A Preliminary Study on Natural Hydrogen Generation Mechanisms Through Hydrothermal Reactions of Banded Iron Formations

In this study, we investigated the potential for hydrogen generation via the hydrothermal oxidation of ferrous iron minerals in the Neoarchean Banded Iron Formation (BIF) of the Wugang region, China.Hydrothermal experiments were conducted in autoclaves, at 150C (30 days) and 230C (22 days), using BIF samples containing a mixture of magnetite and iron silicates.The results confirmed H2 generation in all samples, with quantities increasing with temperature.The high-purity magnetite sample yielded approximately 335 ppm of H 2 at 230C.X-ray diffraction analysis revealed a quantitative correlation between hydrogen production and the oxidation reaction transforming magnetite to hematite.Furthermore, H2 generation was detected even in samples with low magnetite content, suggesting a potential contribution from coexisting iron silicate minerals.This study experimentally demonstrates that BIFs serve as a potential source of geologic hydrogen and identifies magnetite content and temperature as key factors controlling generation efficiency.