Comparison of the sulfiding rate and mechanism of supported NiO and Ni sup 0 particles

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90141-4· OSTI ID:7141914

Mangnus, P J; Landeveld, A.D. van; Moulijn, J A ^[1]; Poels, E K ^[2]

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1. Univ. of Amsterdam (Netherlands)
2. Unilever Research Lab. Vlaardingen (Netherlands)

The sulfiding rate and mechanism of (I) Al{sub 2}O{sub 3}-supported NiO and (II) Al{sub 2}O{sub 3}-supported Ni{sup 0} particles have been studied using the temperature-programmed sulfiding technique. Both the surface and the core of Ni{sup 0} particles are easier to sulfide than those of NiO particles of comparable size. The Ni{sup 0} surface sulfides at 210 K and the inner layers sulfide between 270 and 500 K; simultaneously with the H{sub 2}S uptake H{sub 2} is produced. The surface layer of NiO and Ni{sup 0} surface species takes place at various temperatures because of differences in the elementary steps involved in H{sub 2}S dissociation. Compared to NiO particles, the surface of Ni{sup 0} particles sulfides at lower temperatures due to a higher dissociation rate of H{sub 2}S on these surfaces. The sulfiding rate of the core of the particles is determined by solid-state diffusion. Sulfiding of the core of the Ni{sup 0} particles is determined by the diffusion rate of the Ni{sup {delta}+} and to a lesser extent by the S{sup {delta}+} and to a lesser extent by the S{sup {delta}{minus}} ions, while sulfiding of the core of the NiO particles is most likely limited by diffusion of the O{sup 2{minus}} ions. Surface nickel sulfide species are relatively more stable than their bulk analogues, possibly due to a relatively high entropy content of surface layers.

• OSTI ID: 7141914
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 137:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CONTROL
DIFFUSION
DISSOCIATION
ELEMENTS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
HYDROGENATION
KINETICS
METALS
NICKEL
NICKEL COMPOUNDS
NICKEL OXIDES
NICKEL SULFIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SULFIDATION
SULFIDES
SULFUR COMPOUNDS
SYNTHESIS
TEMPERATURE CONTROL
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS