Tuning the Selectivity of Methanol Decomposition to Syngas Exploiting the Surface Stability of Ni3Sn2 Intermetallic Compounds.

In this work, we explored the catalytic decomposition of methanol to syngas at 300 °C using intermetallic Ni3Sn2 nanoparticles (NPs) synthesized via a chemical route. Our study employed a comprehensive approach combining operando Ambient Pressure soft X-ray absorption spectroscopy with a suite of ex situ techniquesincluding X-ray diffraction, X-ray photoelectron spectroscopy, electron microscopy, and Mössbauer spectroscopyand density functional theory (DFT) calculations. Consistent with the behavior observed in Ni3Sn2 single crystals, we found that the Ni-Sn bonds stabilize the unique electronic structure of the intermetallic Ni active sites, even under strongly oxidizing conditions. Additionally, the nanoparticles exhibit a distinctive morphology characterized by a SnO x -rich protective shell, which further enhances the stability of the Ni sites. These stabilized sites enable the selective decomposition of CH3OH into H2 and CO while effectively suppressing coke formation, a major limitation of conventional metallic Ni catalysts, which are currently a benchmark for this reaction. Our findings suggest a promising strategy for the design of scalable, stable, and cost-effective Ni-based catalysts, unlocking the full potential of methanol as a liquid, portable hydrogen carrier.