Catalytic dehydrogenation of formic acid over palladium nanoparticles immobilized on fibrous mesoporous silica KCC-1

Abstract

Uniform Pd nanoparticles immobilized on N -(3-trimethoxysilylpropyl)diethylenetriamine (PDETA)-functionalized fibrous silica KCC-1 (Pd/KCC-1-PDETA) were prepared with a mean Pd particle size of 2.8 nm. After characterization using powder X-ray diffraction, X-ray photoelectron spectroscopy, and N 2 adsorption-desorption isotherms, Pd/KCC-1-PDETA was used as catalyst for additive-free dehydrogenation of formic acid to produce H 2 . Pd nanoparticle catalysts supported on two other mesoporous silica materials (MSF and KIT-6) were also synthesized to examine how the support affects the reaction. Among the three catalysts, Pd/KCC-1-PDETA exhibited significant catalytic activity (a turnover frequency of 332 h −1 at 323 K and 100% selectivity towards hydrogen), owing to the unique fibrous morphology of KCC-1 and the presence of amine groups that reduced the Pd particle size and improved the access of reactant to the catalytically active Pd sites. The influence of Pd loading (2–10 wt.%), reaction temperature, and reaction time was also examined for the dehydrogenation reaction. Pd/KCC-1-PDETA was recovered easily after the reaction and showed good reusability up to five times without any significant loss in catalytic performance. Highly efficient dehydrogenation of formic acid without any additives at 323 K was achieved using Pd nanoparticles supported on amine-functionalized fibrous silica KCC-1.