Rod-shaped PbW O4 microcrystals of length 1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles（NPs） of different contents（0.5 wt%,1 wt% and 2 wt%） were subsequently deposited ...Rod-shaped PbW O4 microcrystals of length 1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles（NPs） of different contents（0.5 wt%,1 wt% and 2 wt%） were subsequently deposited on the PbW O4 microcrystals,producing robust Pt/PbW O4 composite microcrystals. The PbW O4 microcrystals and Pt/PbW O4 photocatalysts were characterized by X-ray diffraction,N2 sorption measurements,scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron,photoluminescence,Fourier-transform infrared,and ultraviolet-visible diffuse reflectance spectroscopies. The photocatalytic performances of the catalysts were evaluated by the consecutive photocatalytic degradation of acid orange II dye. The Pt/PbW O4 composite microcrystals exhibited high photocatalytic activity and stability. The deposition of Pt NPs produced surface plasmon resonance（SPR）,which induced a large visible light absorption. A Pt NP content of 1-2 wt% resulted in an ~2 times increase in photocatalytic activity,compared with the activity of Pt/PbW O4. The crystal structure and high crystallinity of PbW O4 resulted in its favorable photocatalytic property,and the SPR effect of the Pt NPs promoted visible light harvesting. The Pt NPs also enhanced the separation of photo-generated electrons and holes,which further promoted the photocatalytic reaction.展开更多
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
基金supported by the National Natural Science Foundation of China(2106700421567008+5 种基金21263005)Project of Jiangxi Province Natural Science Foundation China(20133BAB21003)Training Programs of Innovation and Entrepreneurship for Undergraduates of Jiangxi Province(201310407046)The Landing Project of Science and Technology of Colleges and Universities in Jiangxi Province(KJLD14046)Young Scientist Training Project of Jiangxi Province(20122BCB23015)Yuanhang Engineering of Jiangxi Province~~
文摘Rod-shaped PbW O4 microcrystals of length 1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles（NPs） of different contents（0.5 wt%,1 wt% and 2 wt%） were subsequently deposited on the PbW O4 microcrystals,producing robust Pt/PbW O4 composite microcrystals. The PbW O4 microcrystals and Pt/PbW O4 photocatalysts were characterized by X-ray diffraction,N2 sorption measurements,scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron,photoluminescence,Fourier-transform infrared,and ultraviolet-visible diffuse reflectance spectroscopies. The photocatalytic performances of the catalysts were evaluated by the consecutive photocatalytic degradation of acid orange II dye. The Pt/PbW O4 composite microcrystals exhibited high photocatalytic activity and stability. The deposition of Pt NPs produced surface plasmon resonance（SPR）,which induced a large visible light absorption. A Pt NP content of 1-2 wt% resulted in an ~2 times increase in photocatalytic activity,compared with the activity of Pt/PbW O4. The crystal structure and high crystallinity of PbW O4 resulted in its favorable photocatalytic property,and the SPR effect of the Pt NPs promoted visible light harvesting. The Pt NPs also enhanced the separation of photo-generated electrons and holes,which further promoted the photocatalytic reaction.
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.
