Pt/SiO2II. Characterization of the gel and the platinum particles by X-Ray diffraction

Sashital, S. R.

doi:10.1016/0021-9517(77)90060-4

Cited by 93 publications

(3 citation statements)

References 15 publications

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“…The nanosized crystals in Figure exhibit a narrow crystal size distribution. Differences in average crystal sizes determined by TEM and XRPD are probably due to fact that the average crystal size calculated by the Scherrer equation is a ratio of the width of the size distribution, 〈 L 2 〉/〈 L 〉 . Therefore, in relative terms, the largest crystals will contribute more to the average crystal size determined by XRPD than the small crystals.…”

Section: Resultsmentioning

confidence: 99%

Confined Space Synthesis. A Novel Route to Nanosized Zeolites

2000

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Confined space synthesis is a novel method in zeolite synthesis. It involves crystallization of the zeolite inside the pore system of an inert mesoporous matrix. In this way it is possible to prepare nanosized zeolites with a controlled size distribution by proper choice of the inert matrix. Here, confined space synthesis was adopted to prepare nanosized ZSM-5, zeolite Beta, zeolite X, and zeolite A with tailored crystal size distributions using mesoporous carbon blacks as inert matrices. All zeolites were characterized by X-ray powder diffraction, transmission electron microscopy, and nitrogen adsorption/desorption prior to and after removal of the carbon matrix. ZSM-5 with Si/Al ratios of 50, 100, and infinity (silicalite-1) were synthesized with controlled average crystal sizes in the range 20-75 nm. Nanosized zeolite Beta (7-30 nm), zeolite X (22-60 nm), and zeolite A (25-37 nm) were prepared similarly. Removal of the carbon matrix by controlled combustion allows a convenient method for isolation of the pure and highly crystalline zeolites. Therefore, confined space synthesis appears to be an attractive method for preparation of zeolites with a controlled size distribution.

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Section: Resultsmentioning

confidence: 99%

Confined Space Synthesis. A Novel Route to Nanosized Zeolites

2000

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“…to obtain information on distributions when powder X-ray diffraction pattern analysis is undertaken using the Warren-Averbach approach. 26 This approach involves fitting profiles using a Fourier series, as detailed elsewhere. 3 Once account is taken of the effects of instrumental and microstrain broadening effects, average size can be extracted form the first derivative of the cosine coefficients with the size distribution being evident from the second derivative.…”

Section: Discussionmentioning

confidence: 99%

Some considerations related to the use of the Scherrer equation in powder X-ray diffraction as applied to heterogeneous catalysts

Hargreaves

2016

Catalysis, Structure & Reactivity

123

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This short overview summarises some of the basic considerations which should be undertaken when the Scherrer equation is applied to reflection widths in X-ray diffraction patterns of heterogeneous catalysts in order to extract meaningful information. Frequently, little account has been taken of the apparent complications arising from the presence of microstructural strain and disorder such as that which can be introduced upon doping or of anisotropic effects and such considerations are highlighted. Graphical abstract Scanning electron micrograph showing the highly anisotropic nature of biogenic iron oxide found in a natural iron ochre source.

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“…Average metal particle size was estimated using the Scherrer equation. [23] TEM images were taken for determination of the particle size (JEOL, JEM 2010). The samples were dispersed in ethanol with supersonic waves and placed on Cu grids under air atmosphere.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Hydrogenolysis of 1,2‐Propanediol for the Production of Biopropanols from Glycerol

et al. 2010

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Production of propanols from glycerol, which are known as biopropanols, requires catalysts for the hydrogenolysis of 1,2-propanediol, which has been easily derived from glycerol. It is found that the Rh/SiO(2) catalysts modified with ReO(x) species exhibited high activity and selectivity in the hydrogenolysis of 1,2-propanediol to propanols with low selectivity to degradation products and high stability. The optimized Rh--ReO(x)/SiO(2) (Re/Rh=0.5) catalyst gave high yields of 1-propanol (66 %) and propanols (1-propanol +2-propanol) (85 %) in the hydrogenolysis of 1,2-propanediol. In addition, the catalyst was applicable to the one-pot conversion of glycerol to propanols. The structure of Rh metal particles with attached ReO(x) clusters is suggested from the catalyst characterization. It is proposed that 1,2-propanediol hydrogenolysis proceeds by the hydrogenolysis of the alkoxide species on Re with hydrogen species on the Rh metal surface.

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Pt/SiO2II. Characterization of the gel and the platinum particles by X-Ray diffraction

Cited by 93 publications

References 15 publications

Confined Space Synthesis. A Novel Route to Nanosized Zeolites

Confined Space Synthesis. A Novel Route to Nanosized Zeolites

Some considerations related to the use of the Scherrer equation in powder X-ray diffraction as applied to heterogeneous catalysts

Hydrogenolysis of 1,2‐Propanediol for the Production of Biopropanols from Glycerol

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