Dispersed Pd nanoparticles (Pdn) have been synthesized by reducing H2PdCl4 with ethanol, and stabilized using poly(vinylpyrrolidone) (PVP). The Pdn is applied to the glassy carbon substrate to form a thin film, and th...Dispersed Pd nanoparticles (Pdn) have been synthesized by reducing H2PdCl4 with ethanol, and stabilized using poly(vinylpyrrolidone) (PVP). The Pdn is applied to the glassy carbon substrate to form a thin film, and then the potential cyclic scanning at 50 mV·s?1 from ?0.25 to 1.25 V was carried out for about 30 min to form the aggregations of Pdn (Pdn ). FTIR spectroscopy of both transmission and re- ag flection modes was employed to study CO adsorption on Pdn and Pdn in both solid|liquid and solid|gas interfaces. It has ag been revealed that CO adsorption on Pdn film yields two IR bands near 1964 and 1906 cm?1, which are assigned to IR absorption of CO bonded on asymmetric and symmetric bridge sites, respectively. In contrast to the IR properties of CO adsorbed on Pdn, only species of CO bonded on asym- metric bridge sites was determined on Pdn , and the direc- ag tion of the IR band near 1963 cm?1 is completely inverted. The full width at half-maximum (FWHM) of the COB band as near 1964 cm?1 is measured to be 14 cm?1 on Pdn film, while it is 24 cm?1 on Pdn film. The results of the present study ag demonstrated that the inverting of the IR band direction is a general phenomenon that is closely related to the interaction between nanoparticles in aggregation of Pdn.展开更多
文摘Dispersed Pd nanoparticles (Pdn) have been synthesized by reducing H2PdCl4 with ethanol, and stabilized using poly(vinylpyrrolidone) (PVP). The Pdn is applied to the glassy carbon substrate to form a thin film, and then the potential cyclic scanning at 50 mV·s?1 from ?0.25 to 1.25 V was carried out for about 30 min to form the aggregations of Pdn (Pdn ). FTIR spectroscopy of both transmission and re- ag flection modes was employed to study CO adsorption on Pdn and Pdn in both solid|liquid and solid|gas interfaces. It has ag been revealed that CO adsorption on Pdn film yields two IR bands near 1964 and 1906 cm?1, which are assigned to IR absorption of CO bonded on asymmetric and symmetric bridge sites, respectively. In contrast to the IR properties of CO adsorbed on Pdn, only species of CO bonded on asym- metric bridge sites was determined on Pdn , and the direc- ag tion of the IR band near 1963 cm?1 is completely inverted. The full width at half-maximum (FWHM) of the COB band as near 1964 cm?1 is measured to be 14 cm?1 on Pdn film, while it is 24 cm?1 on Pdn film. The results of the present study ag demonstrated that the inverting of the IR band direction is a general phenomenon that is closely related to the interaction between nanoparticles in aggregation of Pdn.
