Multivariate Analysis of the Role of Preparation Conditions on the Intrinsic Properties of a Co-Ni/Al2O3 Steam-Reforming Catalyst
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- 作者：Kelfin M. Hardiman ; Cyrus G. Cooper ; and Adesoji A. Adesina
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2004
- 出版时间：September 15, 2004
- 年：2004
- 卷：43
- 期：19
- 页码：6006 - 6013
- 全文大小：290K
- 年卷期：v.43,no.19(September 15, 2004)
- ISSN：1520-5045
文摘
The effect of major preparation variables on the innate characteristics of an alumina-supportedCo-Ni catalyst system has been examined via a factorial design. Both calcination temperatureand time have statistically significant (negative) effects on the Brunauer-Emmett-Teller surfacearea, with variation in the heating rate registering little or no influence. Similarly, the acid-site strength and concentration were unaffected by variations in the three preparation variables.However, the heating rate was a strong determinant of the metal particle size, dispersion, andmetal surface area. Even so, analysis of the calcination kinetics revealed that a high rate ofmetal aluminate formation was associated with poor dispersion, low metal surface area, andlarge crystallite size especially for low-temperature calcination. The solid-state metal nitratedecomposition implicated an Avrami-Erofeev kinetics with an activation energy of 82.6 kJ mol-1.H2 temperature-programmed reduction and X-ray diffraction revealed the existence of multipleoxide phases, namely, Co3O4, NiO, NiCo2O4, Ni2O3, and Ni(Co)Al2O4, whose magnitude andstability depended on the calcination heating rate. Phase changes during reduction weresupported by scanning electron microscopy and transmission electron microscopy images as wellas surface elemental profiles.