Recyclable High Performance Palladium Heterogeneous Catalyst with Porous PVDF Binder from the Novel Gel Nanocomposite Route

A highly efficient, recyclable, size-tuneable Pd nanoparticle embedded porous heterogeneous catalyst is developed from poly(vinylidene fluoride) (PVDF)/ethylene carbonate (EC)/Pd gel nanocomposite. The dried gel nanocomposite has a fibrillar network structure and Pd nanoparticles of 3-6 nm diameters are dispersed on it. The oxidation of benzoin to benzil and benzyl alcohol to benzoic acid and reduction of nitrobenzene to aniline are studied with the above catalysts in water. The efficiency of the catalyst is dependent on nanoparticle size, and it is 2-2.5 times higher in porous state than that of its sintered (melt-cooled) state. At similar reaction conditions the present porous catalyst has 40 and 80 times higher efficiency than those of previously reported polymer supported Pd catalysts of similar nanoparticle size. The performance of present porous catalyst is 1.7-2.1 times higher than that of impregnated catalyst on PVDF film and it is 1.26-1.30 times more efficient than the same amount of Pd nanoparticle impregnated on activated (porous) carbon. The nanoparticle size remains unchanged even after three cycles of reaction. Possible reasons of the high performance of the present catalyst have been discussed from the multiporosity and site specificity of the binder polymer.