Titre :

Elucidation of deactivation phenomena in cobalt catalyst for Fischer-Tropsch synthesis using SSITKA

Auteur(s) :

Carvalho, Alexandre [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Ordomsky, Vitaly [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Luo, Yuan [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Marinova, Maya [Auteur]
Institut Chevreul - FR2638
Unité Matériaux et Transformations - UMR 8207 [UMET]

Muniz, André R. [Auteur]
Universidade Federal do Rio Grande do Sul [Porto Alegre] [UFRGS]
Marcilio, Nilson Romeu [Auteur]
Universidade Federal do Rio Grande do Sul [Porto Alegre] [UFRGS]
Khodakov, Andrei [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]

Titre de la revue :

Journal of Catalysis

Numéro :

344

Pagination :

669-679

Date de publication :

2016

Discipline(s) HAL :

Chimie/Catalyse

Résumé en anglais : [en]

Catalyst deactivation is a major problem in Fischer-Tropsch synthesis. It leads to a decrease in hydrocarbon productivity and loss of active sites in the expensive cobalt catalyst, and thus, undermines the overall efficiency ...
Lire la suite >Catalyst deactivation is a major problem in Fischer-Tropsch synthesis. It leads to a decrease in hydrocarbon productivity and loss of active sites in the expensive cobalt catalyst, and thus, undermines the overall efficiency of the technology. In the present paper, the effect of deactivation of silica-supported cobalt catalysts and their reductive rejuvenation on the number of active sites and their intrinsic activity (turnover frequency) in Fischer-Tropsch synthesis was studied using a combination of Steady State Isotopic Transient Kinetic Analysis (SSITKA) and catalyst characterization techniques. Catalyst characterization revealed that carbon deposition and agglomeration of cobalt nanoparticles during reaction were responsible for the deactivation. SSITKA experiments showed that the initial rate constant of 2.33 μmol g−1 s−1 had a loss of 67% of activity after 150 h on stream with a reduction in the amount of sites due to deposited carbon by 33.4 μmol g−1. The carbon deposition leads to a decrease in the number of carbon chemisorbed intermediates which yield methane through their hydrogenation and desorption. The number of sites for reversible adsorption of CO is less affected by carbon deposition. The surface hydrogenation sites and surface sites favoring stronger reversible adsorption of carbon monoxide deactivate first during the first hours of Fischer-Tropsch synthesis. Catalyst rejuvenation in hydrogen lessens the amounts of deposited carbon species and partially releases the most active sites of carbon monoxide dissociative adsorption and stronger sites of carbon monoxide reversible adsorption. The transient isotopic methods provide an attractive tool to obtain precise information about the mechanisms of deactivation of cobalt catalysts in Fischer-Tropsch synthesis.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Collections :

• Autres travaux scientifiques

Date de dépôt :

2019-06-17T08:43:19Z
2019-10-16T09:19:56Z
2020-03-16T08:21:05Z
2020-03-16T15:31:19Z