Thermocatalytic Hydrogen Production from Water at Boiling Condition

Abstract Thermochemical water‐splitting cycles are technically feasible for hydrogen production from water. However, the ultrahigh operation temperature and low efficiency seriously restrict their practical application. Herein, one‐step and one‐pot thermocatalytic water‐splitting process is reported at water boiling condition catalyzed by single atomic Pt on defective In₂O₃. Water splitting into hydrogen is verified by D₂O isotopic experiment, with an optimized hydrogen production rate of 36.4 mmol·h⁻¹·g⁻¹ as calculated on Pt active sites. It is revealed that three‐centered Pt₁In₂ surrounding oxygen vacancy as catalytic ensembles promote the dissociation of the adsorbed water into H, which transfers to singlet atomic Pt sites for H₂ production. Remaining OH groups on adjacent In sites from Pt₁In₂ ensembles undergoes O─O bonding, hyperoxide formation and diminishing via triethylamine oxidation, water re‐adsorption for completing the catalytic cycle. Current work represents an isothermal and continuous thermocatalytic water splitting under mild condition, which can re‐awaken the research interest to produce H₂ from water using low‐grade heat and competes with photocatalytic, electrolytic, and photoelectric reactions.