Efficient Geological Hydrogen Production by In Situ High-Throughput System

Hydrogen plays a vital role in the global energy transition, yet current production methods, such as steam reforming and electrolysis, are CO₂-intensive and expensive, respectively. Geological hydrogen (Geo-H₂), produced through the reaction of water with iron-rich rocks (serpentinization), presents a promising, clean, and cost-effective alternative. The Earth's crust contains enough iron to produce hydrogen to supply the global energy need for over 250,000 years. However, slow natural production rates, the difficulty in locating suitable sites with adequate hydrogen accumulation, and challenges in trapping and collecting hydrogen limit its practical application. Stimulated Geo-H₂ production, which involves enhancing the serpentinization reaction by injecting water into subsurface rocks, offers a more controllable and potentially scalable method by optimizing injection fluids and catalysts, paving the way for economically viable large-scale hydrogen production.<br/><br/>In this study, we present an in-situ high-throughput Geo-H₂ production system that significantly accelerates hydrogen generation from natural rocks. Our system achieves a production rate 200 times faster than previously reported, completing the process in just 8 hours. We show that adding as low as 1 wt% of a catalyst can greatly improve hydrogen production. By examining various ionic species and concentrations, we detail their impact on catalytic performance. To uncover the underlying mechanisms at rock-water-gas interface, we employed characterization techniques such as SEM, XRD, XPS, and XANES, along with DFT calculations. We also optimized experimental conditions, including temperature and pH, to enhance efficiency. Our system supports continuous, high-throughput experimentation with real-time sampling and monitoring, allowing data collection as frequently as every three minutes. This advancement represents a significant step forward in studying Geo-H₂ production, providing detailed data and improved accuracy in tracking reaction kinetics. By accelerating Geo-H₂ generation and improving data collection, this study sets the stage for future developments that could make Geo-H₂ a more scalable and efficient source of clean energy.