Probing the Core and Surface Composition of Base-Metal Nanoalloys to Rationalize their Selectivity: The Case of Ni-Fe/SiO 2 Catalysts for the Liquid-Phase Hydrogenation of Furfural

International audience; Bimetallic catalysis for conversion of bio-sourced molecules has often relied on noble metals that should be replaced in the near future by the association of cheaper and more abundant base metals, also known by a poor Z-contrast, which makes in-depth characterization of these systems challenging. However, determining the distribution of base metals in bimetallic nanoparticles is of paramount importance if one wants to rationalize their selectivity. Besides demonstrating that, despite their oxidable character, Ni-Fe catalysts are stable systems for liquid-phase hydroconversion of furfural, this study demonstrates that heterogeneities in the structure of reduced Ni-Fe nanoparticles are key to understanding their catalytic properties, provides a characterization methodology to discriminate between their surface and core compositions, and determines an adequate balance between the two metals that allows tuning the relative rates of the various reaction pathways and, thus, the selectivity.