PVP-stabilized platinum nanoparticles supported on modified silica spheres as efficient catalysts for hydrogen generation from hydrolysis of ammonia borane

Ammonia borane (AB) is considered to be a promising solid hydrogen carrier. In this work, poly(N-vinyl-2-pyrrolidone) (PVP)-protected platinum nanoparticles are supported on γ-methacryloxypropyltrimethoxysilane (γ-MPS) modified silica spheres (Pt-PVP/SiO₂(M)), which are firstly used as highly efficient catalysts for hydrolysis of AB. Platinum nanoparticles possess a tiny size of 2–3 nm and are uniformly dispersed over modified silica spheres. Pt-PVP/SiO₂(M) catalysts with a Pt loading amount of 1.30 wt% show the highest catalytic activity with a turnover frequency (TOF) value of 371 mol_H2 mol_Pt^?1 min^?1 (866 mol_H2 mol_Pt^?1 min^?1 corrected for the surface atoms) at 25 °C. The activation energy is calculated to be 46.2 kJ/mol. Furthermore, owing to the synergistic effect between the modifier of silica spheres and the capping agent of metal nanoparticles, Pt-PVP/SiO₂(M) catalysts have a higher loading amount (8.7 and 6.5 times) and TOF value (4.8 and 5.5 times) than the counterparts prepared without γ-MPS and PVP, respectively.