Tuning the Selectivity of Methanol Decomposition to Syngas Exploiting the Surface Stability of Ni ₃ Sn ₂ 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 SnOx-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.