Covalent triazine framework@silica core–shell spheres decorated with ultrafine platinum nanoparticles: a robust catalyst for selective aqueous phase hydrogenation of butane-2,3-dione and pyruvic acid

Abstract

Sub-nanometric Pt nanoparticles, generated by the metal vapor synthesis technique, were supported on covalent triazine framework@silica (CTF@SiO₂) core–shell hybrid microspheres obtained through polycondensation reactions at the SiO₂ surface. The latter catalyst and a reference system (i.e. Pt nanoparticles deposited on bare SiO₂ microspheres) were screened under identical experimental conditions for the hydrogenation of butane-2,3-dione and pyruvic acid in water, yielding butane-2,3-diol and lactic acid with high selectivity. A combination of catalytic recycling experiments was conducted with both catalysts, along with transmission electron microscopy and X-ray diffraction analyses performed on both the as-synthesized and recovered catalysts, which confirmed the remarkable role of the CTF shell layer in the stabilization of ultrafine Pt NPs against their aggregation under catalysis as well as in enhancing their catalytic activity.