Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carb...Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carbon nanotubes as supports, respectively. TEM and FT IR differential spectra showed that treated carbon nanotubes become short and possess more oxygen containing surface groups. The electrochemical studies indicated that the Pt/treated carbon nanotubes catalyst possessed much higher electrocatalytic activity for the oxidation of methanol than that of the Pt/untreated carbon nanotubes catalyst.展开更多
Effect of carbon nanotubes, as a novel support material, on the performance of Rh-catalyst supported by them was studied. Catalysts based on carbon nanotubes, SiO2, carbon nlolecular sieves, actiye carbon, and GDX-lo2...Effect of carbon nanotubes, as a novel support material, on the performance of Rh-catalyst supported by them was studied. Catalysts based on carbon nanotubes, SiO2, carbon nlolecular sieves, actiye carbon, and GDX-lo2(a copolymer of styrene with divinyIbenzene),were prepared, and their catalytic behaviors for propene hydroformylation were investigated and compared. The results showed that, over the carbon nanotubes-supported Rh-catalyst, C3H6 conversion and regioselectivity of butyric aldehyde (represented by n/i, a ratio of n-butyric aldehyde to its isomer, i-butyric aldehyde, in the products) were pronouncedly improved: the average turnover frequency(TOF) for the catalytic hydroformylation of propene was 0.079 s-1 at 393K, which was 2.1 times faster than that over the Wh catalyst based on SiO2, and the n/i ratio of the aldehyde products reached to 11.6, which was 1.9 times higher than that over the catalyst based on SiO2.The roles of six-membered C-ring at the surface of the carbon-nanotubes on the stability of the catalytically active Rh-complexes and of the tubular nanthchannel on the spatiospecific seletivity of reaction intermediate state and butyric aldehyde produced were discussed.展开更多
Carbon nanotubes were modified by FeSO 4 - H 2 O 2 system,iron hydroxides were adsorbed on the wall of carbon nanotubes simulta neously.These precursors were treated at723K for2h under hydrogen,nitrogen and a ir atmo ...Carbon nanotubes were modified by FeSO 4 - H 2 O 2 system,iron hydroxides were adsorbed on the wall of carbon nanotubes simulta neously.These precursors were treated at723K for2h under hydrogen,nitrogen and a ir atmo - sphere to prepare carbon nanotubes supported γ- Fe 2 O 3 catalyst,γ- Fe 2 O 3 and α- Fe 2 O 3 compound catalyst and amorphous Fe 2 O 3 catalyst,respectively.This is green method to prepare high Fe 2 O 3 loading( ≥ 50%)abstract:catalyst without adding other cation.The different structures Fe 2 O 3 catalysts can be synthesized by controlling the condi - tion of thermal treatment to content active phase requirements for different catalytic reactions.The paper presents a new method to prepare carbon nanotubes supported catalysts.展开更多
文摘Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carbon nanotubes as supports, respectively. TEM and FT IR differential spectra showed that treated carbon nanotubes become short and possess more oxygen containing surface groups. The electrochemical studies indicated that the Pt/treated carbon nanotubes catalyst possessed much higher electrocatalytic activity for the oxidation of methanol than that of the Pt/untreated carbon nanotubes catalyst.
文摘Effect of carbon nanotubes, as a novel support material, on the performance of Rh-catalyst supported by them was studied. Catalysts based on carbon nanotubes, SiO2, carbon nlolecular sieves, actiye carbon, and GDX-lo2(a copolymer of styrene with divinyIbenzene),were prepared, and their catalytic behaviors for propene hydroformylation were investigated and compared. The results showed that, over the carbon nanotubes-supported Rh-catalyst, C3H6 conversion and regioselectivity of butyric aldehyde (represented by n/i, a ratio of n-butyric aldehyde to its isomer, i-butyric aldehyde, in the products) were pronouncedly improved: the average turnover frequency(TOF) for the catalytic hydroformylation of propene was 0.079 s-1 at 393K, which was 2.1 times faster than that over the Wh catalyst based on SiO2, and the n/i ratio of the aldehyde products reached to 11.6, which was 1.9 times higher than that over the catalyst based on SiO2.The roles of six-membered C-ring at the surface of the carbon-nanotubes on the stability of the catalytically active Rh-complexes and of the tubular nanthchannel on the spatiospecific seletivity of reaction intermediate state and butyric aldehyde produced were discussed.
文摘Carbon nanotubes were modified by FeSO 4 - H 2 O 2 system,iron hydroxides were adsorbed on the wall of carbon nanotubes simulta neously.These precursors were treated at723K for2h under hydrogen,nitrogen and a ir atmo - sphere to prepare carbon nanotubes supported γ- Fe 2 O 3 catalyst,γ- Fe 2 O 3 and α- Fe 2 O 3 compound catalyst and amorphous Fe 2 O 3 catalyst,respectively.This is green method to prepare high Fe 2 O 3 loading( ≥ 50%)abstract:catalyst without adding other cation.The different structures Fe 2 O 3 catalysts can be synthesized by controlling the condi - tion of thermal treatment to content active phase requirements for different catalytic reactions.The paper presents a new method to prepare carbon nanotubes supported catalysts.
