Pd nanoparticles anchoring to core-shell Fe3O4@SiO2-porous carbon catalysts for ammonia borane hydrolysis

Abstract

A modified Stöber method is applied to synthesize the magnetic core-shell Fe3O4@SiO2 particles, followed by compositing a series of porous glucose-derived carbon with ZnCl2 as etchant. Then, ultrafine Pd nanoparticles (NPs) are successfully anchored to the resulting Fe3O4@SiO2-PC composites with an in-situ reduction strategy. The particle sizes of Pd NPs are mainly centered in the range of 2.3–4.3 nm in the as-prepared Pd/Fe3O4@SiO2-PC catalysts, owning a hierarchical porous structure with high specific surface area (SBET = 626.0 m2 g−1) and large pore volume (Vp = 0.61 cm3 g−1). Their catalytic behavior for the hydrogen generation from ammonia borane (AB) hydrolysis is investigated in details. The corresponding apparent activation energy is as low as 28.4 kJ mol−1 and the reaction orders with AB and Pd concentrations are near zero and 1.10 under the present conditions, respectively. In addition, the magnetic catalysts, which could be easily separated out by a magnet, are still highly active even after nine runs, revealing their excellent reusability.