Core–shell nanospheres Pt@SiO₂ for catalytic hydrogen production

Highlights: • Pt@SiO₂ core–shell NPs are synthesized via a simple one-pot synthetic route. • Ultrafine Pt NPs (∼4 nm) are embedded in well-proportioned SiO₂ nanospheres. • Pt@SiO₂ shows a high activity and good durability for H₂ generation from AB. - Abstract: Ultrafine platinum nanoparticles (NPs) embedded in silica nanospheres (Pt@SiO₂) have been synthesized in a NP-5/cyclohexane reversed-micelle system followed by NaBH₄ reduction. The as-synthesized core–shell nanocatalysts Pt@SiO₂ were characterized by scanning electron microscopy, transmission electron microscopes, X-ray powder diffraction analysis, energy dispersive X-ray spectrometer and nitrogen adsorption–desorption investigations. Interestingly, the as-synthesized core–shell nanocatalysts Pt@SiO₂ showed an excellent catalytic performance in hydrogen generation from the hydrolysis of ammonia borane (BH₃NH₃, AB) at room temperature. Especially, the catalytic performance of the Pt@SiO₂ remained almost unchanged after the five recycles and even after the heat treatment (673 K), because the silica shells inhibit aggregation or deformation of the metal cores. Besides, the kinetic studies showed that the catalytic hydrolysis of AB was first order with respect to the catalyst concentration and zero order with respect to the substrate concentration, respectively. The excellent catalytic activity and stability of Pt@SiO₂ can make it have a bright future in the practical application