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Nanoceria supported palladium(0) nanoparticles: Superb catalyst in dehydrogenation of formic acid at room temperature

Akbayrak, Serdar
Özkar, Saim
Highly efficient dehydrogenation of formic acid (FA) at room temperature was achieved using palladium(0) nanoparticles supported on nanoceria (Pd-0/CeO2) as catalysts. Pd-0/CeO2 was prepared by impregnation of palladium(II) ions on the surface of ceria followed by their reduction with sodium borohydride in aqueous solution at room temperature. Pd((0)/CeO2 was isolated from the reaction solution by centrifugation and characterized by a combination of advanced analytical techniques. The catalytic activity of Pd-0/CeO2 samples with various Pd loading in the range 1.0-5.0% wt was tested in dehydrogenation of formic acid plus sodium formate with a molar ratio of FA/SF = 1/9. Pd-0/CeO2 with Pd loading of 2.27% wt shows superb catalytic activity in dehydrogenation of FA with a turnover frequency (TOF) value of 1400 h(-1) at 25.0 +/- 0.1 degrees C. The superb catalytic activity of Pd-0/CeO2 is ascribed to the reducible nature of ceria during the decomposition of FA (HCO2H -> CO2+H-2). The kinetic data, obtained by measuring the volume of pure H-2 gas, could be converted to the change in concentration of FA by considering the equilibrium between the formate ion and formic acid (HCO2H reversible arrow HCOO- + H3O+). The FA concentration versus time data fit to the first order kinetics with respect to the FA concentration.