Influence of catalyst variation on underground hydrogen generation in gas reservoirs: Impact on hydrogen yield and alteration of catalyst structure and rock properties

Experimental and numerical studies highlight the potential of subsurface hydrogen production to generate substantial quantities of hydrogen, however certain aspects remain unclear. One such aspect involves the application of catalysts, including their delivery and efficiency in reservoir porous media. This study explores in situ hydrogen generation in a natural gas reservoir using Ni/Al2O3, Nb-doped Ni/Al2O3, and in situ synthesized Ni-based catalysts. Laboratory experiments tested two catalyst delivery methods in flow reactors and a combustion tube under conditions of up to 800 °C and 8 MPa. Results indicate in situ synthesized catalysts provide superior distribution and stable hydrogen synthesis, reaching up to 48.4 vol%, while industrial catalysts met some benchmarks but proved less effective for in situ use. The findings confirm the feasibility and safety of this approach, highlighting critical factors affecting hydrogen generation efficiency and its practical potential.