Crystallographic alignment and phonon corridors: Enhanced hydrogen production via engineered thermal pathways in ultramafic rocks

The optimization of subsurface hydrogen generation is limited by fundamental heat transport constraints affecting water-rock reactions. Here, we experimentally validate the Supracrystalline Phonon-Aligned Reaction Corridor (SPARC) framework, demonstrating that crystallographic fabric alignment at mesoscopic scales (10⁻⁶ to 10⁻² m) creates preferential thermal pathways, significantly enhancing hydrogen yields from serpentinization and radiolytic processes. Using a proprietary nitrogen hybrid nanofoam (95% N₂, 0.6–0.8% Al₂O₃, 0.3–0.5% SiO₂ nanoparticles), we engineered aligned fracture networks in olivine-rich cores, achieving pronounced thermal anisotropy. Directional thermal conductivity along SPARC-aligned corridors reached 30.5 ± 1.2 W/m·K—over three times higher than perpendicular orientations and conventional systems. Phonon coherence lengths extended to ~50 nm in aligned systems, compared to <1 nm in isotropic matrices. Flow-through experiments at 200°C and 100 bar over 60 days showed SPARC-treated samples retained 88% of fracture aperture and produced 78% more hydrogen than controls (32 vs. 18 mmol/kg). Reaction front propagation increased by 63% in aligned domains, directly correlating with higher hydrogen yields. Introducing CO₂ resulted in a six-fold increase in methane generation in SPARC systems (170 vs. 30 μmol/kg), indicating improved catalytic efficiency. Comprehensive characterization—using electron backscatter diffraction, micro-CT, laser flash analysis, thermoreflectance, and fluid chemistry monitoring—established the link between structural alignment, thermal transport, and reaction productivity. These results demonstrate that SPARC transforms thermal barriers into conductive channels, overcoming limitations in serpentinization. This engineered approach offers significant potential for geothermal energy, subsurface hydrogen development, and carbon mineralization, accelerating the deployment of geological hydrogen as a clean energy carrier.