Palladium silica nanosphere-catalyzed decomposition of formic acid for chemical hydrogen storage

Abstract

Palladium nanoparticles (Pd NPs) encapsulated within hollow silica nanospheres (Pd@SiO₂) (20–35 nm) were synthesized using Pd(NH₃)₄Cl₂ as precursor in a polyoxyethylene-nonylphenyl ether/cyclohexane reversed micelle system followed by NaBH₄ reduction. Pd NPs supported on silica nanospheres (Pd/SiO₂) were prepared by the conventional impregnation of Pd(NH₃)₄Cl₂ precursor to silica nanospheres, which were prepared using a similar reversed micelle system without Pd precursor, followed by NaBH₄ reduction. The as-sythesized Pd@SiO₂ and Pd/SiO₂ catalysts have high catalytic activities, in comparison to Pd NPs supported on commercial silica, for the decomposition of formic acid at convenient temperature for chemical hydrogen storage. Remarkably, it has been observed that the interactions of the Pd nanoparticles with surface groups of silica supports are important for the catalytic performance.