Hydrogen Production Mechanism in Low-Temperature Methanol Decomposition Catalyzed by NiSn Intermetallic Compound: A Combined Operando and Density Functional Theory Investigation.

Hydrogen production from methanol decomposition to syngas (H + CO) is a promising alternative route for clean energy transition. One major challenge is related to the quest for stable, cost-effective, and selective catalysts operating below 400 °C. We illustrate an investigation of the surface reactivity of a NiSn catalyst working at 250 °C, by combining density functional theory, operando X-ray absorption spectroscopy, and high-resolution transmission electron microscopy. We discovered that the catalytic reaction is driven by surface tin-oxide phases, which protects the underlying Ni atoms from irreversible chemical modifications, increasing the catalyst durability. Moreover, we found that Sn content plays a key role in enhancing the H selectivity, with respect to secondary products such as CO. These findings open new perspectives for the engineering of scalable and low-cost catalysts for hydrogen production.