Original ResearchPublished 7 September 2026Experimental investigation of hydrogen solubility in water, NaCl solutions, and deep saline reservoir fluids from the Ketzin site under subsurface conditionsNora Wolff · Mrityunjay Singh · Ronny Giese · Erik Spangenberg · Cornelia Schmidt-HattenbergerFrontiers in Energy Researchdoi 10.3389/fenrg.2026.1919332