*GLADIATOR*
عضو جدید
سلام دوستان
دو تا ABSTRACT از دو تا مقاله Sciencedirect گذاشتم اگه امکانش هست برام ترجمشون کنید واسه پایان نامم خیلی بهشون احتیاج دارم. ضمیمش هم کردم
مرسی
Abstract .1
Aseries of calcium oxide promoted cobalt catalystswere prepared by incipientwetness impregnation. The
influence of the calcium oxide on the dispersion, reducibility and cobalt particle size of the catalysts was
studied by different techniques, including N2 adsorption, X-ray diffraction, temperature-programmed
reduction, temperature-programmed desorption and oxygen titration. It was found that calcium oxide
improved the cobalt oxide reducibility, especially for the reduction of CoO to Co0. Since the interaction
between cobalt oxide and the calcium oxide promoted support was suppressed, larger Co3O4 particles
were formed on the surface. The catalytic activity for Fischer–Tropsch synthesis was evaluated in a continuous
stirred tank reactor (CSTR). A positive correlation was observed between CO conversion, C5+
selectivity and calcium oxide content. Furthermore, methane selectivity decreased with increasing calcium
oxide content. These could be attributed to the enhanced reducibility that provides abundant active
sites.
Abstract .2
Passivation of highly dispersed metal catalysts after reduction is necessary prior to exposure to air due to the exothermicity
of metal oxidation. This exothermicity can result in a significant increase in temperature of the catalyst resulting in catalyst
degradation and a potential fire hazard. This paper reports the results of a study of passivation of Ru-promoted Co/alumina.
Passivations using CO and CO+H2 mixtures were compared to the standard method of passivation using small concentrations
of O2. Passivation by CO+H2 resulted in a lower temperature rise upon exposure to air than oxygen passivation. Passivation
usingCO/H2 = 10 resulted in a catalyst whose catalytic activity forCOhydrogenationwas able to be recovered after exposure
to air by re-reduction similar to after oxygen passivation. CO passivation yielded a catalyst that was not able to be as well
recovered upon re-reduction, probably due to the formation of graphitic carbon. Exposure of the CO/H2 passivated catalyst
to air for at least 90 min actually made it easier to recover the original activity upon re-reduction. This is probably related to
the oxidation of the carbidic passivation layer during air exposure. © 2002 Elsevier Science B.V. All rights reserved.
دو تا ABSTRACT از دو تا مقاله Sciencedirect گذاشتم اگه امکانش هست برام ترجمشون کنید واسه پایان نامم خیلی بهشون احتیاج دارم. ضمیمش هم کردم
مرسی
Abstract .1
Aseries of calcium oxide promoted cobalt catalystswere prepared by incipientwetness impregnation. The
influence of the calcium oxide on the dispersion, reducibility and cobalt particle size of the catalysts was
studied by different techniques, including N2 adsorption, X-ray diffraction, temperature-programmed
reduction, temperature-programmed desorption and oxygen titration. It was found that calcium oxide
improved the cobalt oxide reducibility, especially for the reduction of CoO to Co0. Since the interaction
between cobalt oxide and the calcium oxide promoted support was suppressed, larger Co3O4 particles
were formed on the surface. The catalytic activity for Fischer–Tropsch synthesis was evaluated in a continuous
stirred tank reactor (CSTR). A positive correlation was observed between CO conversion, C5+
selectivity and calcium oxide content. Furthermore, methane selectivity decreased with increasing calcium
oxide content. These could be attributed to the enhanced reducibility that provides abundant active
sites.
Abstract .2
Passivation of highly dispersed metal catalysts after reduction is necessary prior to exposure to air due to the exothermicity
of metal oxidation. This exothermicity can result in a significant increase in temperature of the catalyst resulting in catalyst
degradation and a potential fire hazard. This paper reports the results of a study of passivation of Ru-promoted Co/alumina.
Passivations using CO and CO+H2 mixtures were compared to the standard method of passivation using small concentrations
of O2. Passivation by CO+H2 resulted in a lower temperature rise upon exposure to air than oxygen passivation. Passivation
usingCO/H2 = 10 resulted in a catalyst whose catalytic activity forCOhydrogenationwas able to be recovered after exposure
to air by re-reduction similar to after oxygen passivation. CO passivation yielded a catalyst that was not able to be as well
recovered upon re-reduction, probably due to the formation of graphitic carbon. Exposure of the CO/H2 passivated catalyst
to air for at least 90 min actually made it easier to recover the original activity upon re-reduction. This is probably related to
the oxidation of the carbidic passivation layer during air exposure. © 2002 Elsevier Science B.V. All rights reserved.
