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Ca-Modiﬁed Co/SBA-15 Catalysts for Hydrogen Production through Ethanol Steam Reforming

100%

Chiou J. Y. Z. , Liu S. W. , Ho K. F. , Huang H. H. , Tang C. W. , Wang C. B.

tom Vol. 5

1--16

Hydrogen production through steam reforming of ethanol (SRE) over the Ca-modified Co/SBA-15 catalysts was studied herein to evaluate the catalytic activity, stability andthebehavior of coke deposition.The Ca-modified SBA-15 supports were prepared from the Ca(NO3)2•4H2O (10 wt%) which was incorporated to SBA-15 by incipient wetness impregnation (assigned as Ca/SBA-15) and direct hydrothermal (assigned as Ca-SBA-15) method. The active cobalt species from the Co(NO3)2•6H2O (10 wt%) was loaded to SiO2, SBA-15 and modified-SBA-15 supports with incipient wetness impregnation method to obtain the cobalt catalysts (named as Co/SiO2, Co/SBA-15, Co-Ca/SBA-15 and Co/Ca-SBA-15, respectively). The prepared catalysts were characterized by using X-ray diffraction (XRD), temperature programmed reduction (TPR), transmission electron microscopy (TEM) and BET.The catalytic performance of the SRE reaction was evaluated in a fixed-bed reactor.The results indicated that the Co/Ca-SBA-15 catalystwas preferential among these catalysts and the ethanol can be converted completely at 375 °C. The hydrogen yield (YH2) approached 4.76 at 500 °C and less coke deposited. Further, the long-term stabilitytest of this catalyst approached100h at 500 °C and did not deactivate.

Katalizatory kobaltowo-molibdenowe domieszkowane cezem do syntezy amoniaku

63%

Moszyński D. , Adamski P. , Pełech I. , Arabczyk W.

2015

tom T. 94, nr 8

1399-1403

Badano katalizatory kobaltowo-molibdenowe domieszkowane cezem (0,25–3% mas. Cs) w procesie syntezy amoniaku. W katalizatorach tych zidentyfikowano dwie fazy krystaliczne azotków kobaltu i molibdenu: Co₂Mo₃N oraz Co₃Mo₃N. Wykazano, że materiały te charakteryzują się dużą aktywnością w procesie syntezy amoniaku. Optymalną aktywność katalityczną uzyskano dla katalizatorów zawierających 1,7% mas. cezu. Na podstawie testu starzenia termicznego wykazano, że dochodzi do częściowego spiekania krystalitów fazy repeatedly detd. Thermal treatment resulted in sintering of crystallite Co₃Mo₃N phase and decreasing the activity of catalysts.N oraz zmniejszenia powierzchni właściwej. W rezultacie zmniejsza się aktywność katalizatorów.

Co-Mo catalysts contg. Cs (0.25–3.0% by mass) were obtained by redn. of precursors with NH₃ at 700°C. The precursors were derived from aq. solns. of (NH₄)₆Mo₇O₂₄, Co(NO₃)₂ and CsOH. The anal. of catalysts by X-ray diffraction and anal. of the diffraction profiles by Rietveld method showed the presence of Co₂Mo₃N and Co₃Mo₃N phases depending on the content of Cs in the catalyst. Activities of the catalysts were tested under lab. Conditions of the synthesis of NH₃ at 400°C and 10 MPa. The reaction rate const. was detd. by measuring the flow of the reaction gases and NH₃ concns. The highest activity was achieved for the catalyst contg. Cs 1.7% by mass. The catalysts used for the activity detns. were then subjected to aging (650°C, 18 h) and their activity was repeatedly detd. Thermal treatment resulted in sintering of crystallite Co₃Mo₃N phase and decreasing the activity of catalysts.