Evidence of hydrogen release during CO₂ sequestration in basalt

Addressing climate change requires effective carbon sequestration techniques, with geological storage in basalt formations being a prime candidate due to their widespread availability and capacity for mineral carbonation. This study explores CO₂-basalt interactions under subsurface conditions, focusing on incidental hydrogen (H₂) generation. Controlled experiments at 5 MPa and temperatures between 323K and 373K reveal preliminary evidence of H₂ release, measured up to 0.18 wt% of the gas phase during CO₂ injection into basalt. Total Inorganic Carbon (TIC) measurements provide direct evidence of carbon sequestration, with values increasing from a baseline of 20.9 mg/L to 463 mg/L and 468 mg/L at 323K and 373K, respectively. These findings enhance our understanding of basaltic carbon sequestration mechanics and suggest a potential avenue for H₂ production alongside carbon storage. This study presents the first experimental evidence of H₂ generation during CO₂ sequestration in basalt under controlled subsurface conditions, highlighting potential dual benefits for carbon storage and clean energy production.