Low-Temperature Hydrogen Deoxygenation over Pd and Pt Catalysts: Metal and Precursor Effects

High Resolution Image Download MS PowerPoint Slide Removal of trace oxygen at low temperature is essential for the deployment of hydrogen from water electrolysis, yet catalyst design for this deoxygenation catalysis remains largely empirical due to an incomplete understanding of metal-precursor effects. Here, we decouple metal identity (Pd vs Pt) and precursor chemistry (nitrate vs chloride) in Al 2 O 3 -supported noble-metal catalysts for hydrogen deoxygenation. Pd exhibits intrinsically higher activity than Pt, arising from a lower barrier for the rate-determining OH* hydrogenation step and a more effective supply of activated hydrogen. In contrast, chloride-derived species act as reversible electronic modulators that stabilize metal centers, suppress reactant adsorption, and increase the activation barrier of the rate-determining step, thereby diminishing activity without permanently deactivating the catalyst. Eliminating chloride effects restores the intrinsic reactivity of the metal sites. Guided by this precursor-oriented electronic insight, the catalyst maintains efficient oxygen removal at 40 °C under a high weight hourly space velocity of 120,000 mL g −1 h −1, and exhibits stable operation over 1000 h at an initial oxygen concentration of 0.6% in industrial-scale tests, while achieving a low deoxygenation cost of 0.007 US$ Nm −3 . This work guides optimizing both metal selection and precursor engineering in the design of an industrial catalyst.