Palladium(0) nanoparticles supported on ceria: Highly active and reusable catalyst in hydrogen generation from the hydrolysis of ammonia borane

Abstract

Palladium(0) nanoparticles supported on nanoceria (Pd0/CeO2) were prepared by the impregnation of palladium(II) ions on the surface of ceria followed by their reduction with sodium borohydride in aqueous solution at room temperature. Pd0/CeO2 were isolated from the reaction solution by centrifugation and characterized by ICP-OES, XRD, TEM, SEM-EDS and XPS techniques. All the results reveal that palladium(0) nanoparticles were uniformly dispersed on ceria and the resulting Pd0/CeO2 are highly active and reusable catalysts in hydrogen generation from the hydrolysis of ammonia borane with a turnover frequency value of 29 min−1 at 25.0 ± 0.1 °C. The catalytic activity of Pd0/CeO2 in hydrogen generation from the hydrolysis of ammonia borane is higher compared to that of other palladium based catalysts such as Pd0/ZrO2, Pd0/SiO2, Pd0/Al2O3, Pd0/TiO2 under the same conditions. The catalytic activity of Pd0/CeO2 samples with various palladium loading in the range of 1.0–5.0% wt Pd was tested in hydrogen generation from the hydrolysis of ammonia borane at 25.0 ± 0.1 °C. The highest catalytic activity was achieved by using 1.18% wt palladium loaded ceria. The reusability tests reveal that Pd0/CeO2 are still active in the subsequent runs of hydrolysis of ammonia borane preserving 47% of the initial catalytic activity even after the fifth run of hydrolysis. Our report also includes the results of kinetic study of the catalytic hydrolysis of ammonia borane depending on the temperature and catalyst concentration.