Advances in Catalyst Deactivation

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (30 September 2014) | Viewed by 170272

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Special Issue Editors

BYU Catalysis Lab, Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
Interests: heterogeneous catalysis (catalyst design; reaction kinetics; adsorption phenomena; catalyst deactivation; syngas conversion catalysis; fischer-tropsch synthesis; SCR; automotive emissions control)
Chemical Engineering Department, Brigham Young University, Provo, UT 84602, USA
Interests: heterogeneous catalysis; energy engineering; plasma reactions; coal gasification; carbon dioxide capture and storage
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Special Issue Information

Dear Colleagues,

Catalyst deactivation, the loss over time of catalytic activity and/or selectivity, is a problem of great and continuing concern in the practice of industrial catalytic processes. Costs to industry for catalyst replacement and process shutdown total tens of billions of dollars per year. While catalyst deactivation is inevitable for most processes, some of its immediate, drastic consequences may be avoided, postponed, or even reversed. Accordingly, there is considerable motivation to better understand catalyst decay and regeneration.  Indeed, the science of catalyst deactivation and regeneration has been developing rapidly as evidenced by the considerable literature addressing this topic, including 21,000 journal articles, presentations, reports, reviews, and books; and more than 29,000 patents for the period of 1980 to 2012. This developing science provides the foundation for continuing, substantial improvements in the efficiency and economics of catalytic processes through development of catalyst deactivation models, more stable catalysts, and regeneration processes.

This special issue focuses on recent advances in catalyst deactivation and regeneration, including advances in (1) scientific understanding of mechanisms; (2) development of improved methods and tools for investigation; and (3) more robust models of deactivation and regeneration.

Prof. Calvin H. Bartholomew
Dr. Morris D. Argyle
Guest Editors

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Keywords

  • catalyst deactivation
  • catalyst regeneration
  • deactivation and regeneration
  • catalyst
  • catalyst deactivation and regeneration in
    • mechanisms
    • models
    • methods of study
    • kinetics
    • poisoning
    • sintering
    • fouling
    • mechanical degradation
    • stability improvements
    • Fischer-Tropsch synthesis
    • Methanol synthesis
    • Hydrotreating
    • Selective catalytic reduction of NOx

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Published Papers (9 papers)

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Editorial

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224 KiB  
Editorial
Advances in Catalyst Deactivation and Regeneration
by Calvin H. Bartholomew and Morris D. Argyle
Catalysts 2015, 5(2), 949-954; https://doi.org/10.3390/catal5020949 - 11 Jun 2015
Cited by 30 | Viewed by 6689
Abstract
Catalyst deactivation, the loss over time of catalytic activity and/or selectivity, is a problem of great and continuing concern in the practice of industrial catalytic processes. Costs to industry for catalyst replacement and process shutdown total tens of billions of dollars per [...] Read more.
Catalyst deactivation, the loss over time of catalytic activity and/or selectivity, is a problem of great and continuing concern in the practice of industrial catalytic processes. Costs to industry for catalyst replacement and process shutdown total tens of billions of dollars per year. [...] Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)

Research

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11807 KiB  
Article
Effect of Ce and Zr Addition to Ni/SiO2 Catalysts for Hydrogen Production through Ethanol Steam Reforming
by Jose Antonio Calles, Alicia Carrero, Arturo Javier Vizcaíno and Montaña Lindo
Catalysts 2015, 5(1), 58-76; https://doi.org/10.3390/catal5010058 - 30 Jan 2015
Cited by 37 | Viewed by 9479
Abstract
A series of Ni/Ce\(_{x}\)Zr\(_{1-x}\)O\(_{2}\)/SiO\(_{2}\) catalysts with different Zr/Ce mass ratios were prepared by incipient wetness impregnation. Ni/SiO\(_{2}\), Ni/CeO\(_{2}\) and Ni/ZrO\(_{2}\) were also prepared as reference materials to compare. Catalysts' performances were tested in ethanol steam reforming for hydrogen production and characterized by XRD, [...] Read more.
A series of Ni/Ce\(_{x}\)Zr\(_{1-x}\)O\(_{2}\)/SiO\(_{2}\) catalysts with different Zr/Ce mass ratios were prepared by incipient wetness impregnation. Ni/SiO\(_{2}\), Ni/CeO\(_{2}\) and Ni/ZrO\(_{2}\) were also prepared as reference materials to compare. Catalysts' performances were tested in ethanol steam reforming for hydrogen production and characterized by XRD, H\(_{2}\)-temperature programmed reduction (TPR), NH\(_{3}\)-temperature programmed desorption (TPD), TEM, ICP-AES and N\(_{2}\)-sorption measurements. The Ni/SiO\(_{2}\) catalyst led to a higher hydrogen selectivity than Ni/CeO\(_{2}\) and Ni/ZrO\(_{2}\), but it could not maintain complete ethanol conversion due to deactivation. The incorporation of Ce or Zr prior to Ni on the silica support resulted in catalysts with better performance for steam reforming, keeping complete ethanol conversion over time. When both Zr and Ce were incorporated into the catalyst, Ce\(_{x}\)Zr\(_{1-x}\)O\(_{2}\) solid solution was formed, as confirmed by XRD analyses. TPR results revealed stronger Ni-support interaction in the Ce\(_{x}\)Zr\(_{1-x}\)O\(_{2}\)-modified catalysts than in Ni/SiO\(_{2}\) one, which can be attributed to an increase of the dispersion of Ni species. All of the Ni/Ce\(_{x}\)Zr\(_{1-x}\)O\(_{2}\)/SiO\(_{2}\) catalysts exhibited good catalytic activity and stability after 8 h of time on stream at 600°. The best catalytic performance in terms of hydrogen selectivity was achieved when the Zr/Ce mass ratio was three. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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1490 KiB  
Article
Inhibition of a Gold-Based Catalyst in Benzyl Alcohol Oxidation: Understanding and Remediation
by Emmanuel Skupien, Rob J. Berger, Vera P. Santos, Jorge Gascon, Michiel Makkee, Michiel T. Kreutzer, Patricia J. Kooyman, Jacob A. Moulijn and Freek Kapteijn
Catalysts 2014, 4(2), 89-115; https://doi.org/10.3390/catal4020089 - 15 Apr 2014
Cited by 40 | Viewed by 12921
Abstract
Benzyl alcohol oxidation was carried out in toluene as solvent, in the presence of the potentially inhibiting oxidation products benzaldehyde and benzoic acid. Benzoic acid, or a product of benzoic acid, is identified to be the inhibiting species. The presence of a basic [...] Read more.
Benzyl alcohol oxidation was carried out in toluene as solvent, in the presence of the potentially inhibiting oxidation products benzaldehyde and benzoic acid. Benzoic acid, or a product of benzoic acid, is identified to be the inhibiting species. The presence of a basic potassium salt (K2CO3 or KF) suppresses this inhibition, but promotes the formation of benzyl benzoate from the alcohol and aldehyde. When a small amount of water is added together with the potassium salt, an even greater beneficial effect is observed, due to a synergistic effect with the base. A kinetic model, based on the three main reactions and four major reaction components, is presented to describe the concentration-time profiles and inhibition. The inhibition, as well as the effect of the base, was captured in the kinetic model, by combining strong benzoic acid adsorption and competitive adsorption with benzyl alcohol. The effect of the potassium salt is accounted for in terms of neutralization of benzoic acid. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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379 KiB  
Article
Investigation of the Deactivation Phenomena Occurring in the Cyclohexane Photocatalytic Oxidative Dehydrogenation on MoOx/TiO2 through Gas Phase and in situ DRIFTS Analyses
by Vincenzo Vaiano, Diana Sannino, Ana Rita Almeida, Guido Mul and Paolo Ciambelli
Catalysts 2013, 3(4), 978-997; https://doi.org/10.3390/catal3040978 - 13 Dec 2013
Cited by 11 | Viewed by 6667
Abstract
In this work, the results of gas phase cyclohexane photocatalytic oxidative dehydrogenation on MoOx/SO4/TiO2 catalysts with DRIFTS analysis are presented. Analysis of products in the gas-phase discharge of a fixed bed photoreactor was coupled with in situ monitoring [...] Read more.
In this work, the results of gas phase cyclohexane photocatalytic oxidative dehydrogenation on MoOx/SO4/TiO2 catalysts with DRIFTS analysis are presented. Analysis of products in the gas-phase discharge of a fixed bed photoreactor was coupled with in situ monitoring of the photocatalyst surface during irradiation with an IR probe. An interaction between cyclohexane and surface sulfates was found by DRIFTS analysis in the absence of UV irradiation, showing evidence of the formation of an organo-sulfur compound. In particular, in the absence of irradiation, sulfate species initiate a redox reaction through hydrogen abstraction of cyclohexane and formation of sulfate (IV) species. In previous studies, it was concluded that reduction of the sulfate (IV) species via hydrogen abstraction during UV irradiation may produce gas phase SO2 and thereby loss of surface sulfur species. Gas phase analysis showed that the presence of MoOx species, at same sulfate loading, changes the selectivity of the photoreaction, promoting the formation of benzene. The amount of surface sulfate influenced benzene yield, which decreases when the sulfate coverage is lower. During irradiation, a strong deactivation was observed due to the poisoning of the surface by carbon deposits strongly adsorbed on catalyst surface. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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Review

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4548 KiB  
Review
Deactivation of Pd Catalysts by Water during Low Temperature Methane Oxidation Relevant to Natural Gas Vehicle Converters
by Rahman Gholami, Mina Alyani and Kevin J. Smith
Catalysts 2015, 5(2), 561-594; https://doi.org/10.3390/catal5020561 - 31 Mar 2015
Cited by 176 | Viewed by 12202
Abstract
Effects of H2O on the activity and deactivation of Pd catalysts used for the oxidation of unburned CH4 present in the exhaust gas of natural-gas vehicles (NGVs) are reviewed. CH4 oxidation in a catalytic converter is limited by low [...] Read more.
Effects of H2O on the activity and deactivation of Pd catalysts used for the oxidation of unburned CH4 present in the exhaust gas of natural-gas vehicles (NGVs) are reviewed. CH4 oxidation in a catalytic converter is limited by low exhaust gas temperatures (500–550 °C) and low concentrations of CH4 (400–1500 ppmv) that must be reacted in the presence of large quantities of H2O (10–15%) and CO2 (15%), under transient exhaust gas flows, temperatures, and compositions. Although Pd catalysts have the highest known activity for CH4 oxidation, water-induced sintering and reaction inhibition by H2O deactivate these catalysts. Recent studies have shown the reversible inhibition by H2O adsorption causes a significant drop in catalyst activity at lower reaction temperatures (below 450 °C), but its effect decreases (water adsorption becomes more reversible) with increasing reaction temperature. Thus above 500 °C H2O inhibition is negligible, while Pd sintering and occlusion by support species become more important. H2O inhibition is postulated to occur by either formation of relatively stable Pd(OH)2 and/or partial blocking by OH groups of the O exchange between the support and Pd active sites thereby suppressing catalytic activity. Evidence from FTIR and isotopic labeling favors the latter route. Pd catalyst design, including incorporation of a second noble metal (Rh or Pt) and supports high O mobility (e.g., CeO2) are known to improve catalyst activity and stability. Kinetic studies of CH4 oxidation at conditions relevant to natural gas vehicles have quantified the thermodynamics and kinetics of competitive H2O adsorption and Pd(OH)2 formation, but none have addressed effects of H2O on O mobility. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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4697 KiB  
Review
Deactivation and Regeneration of Commercial Type Fischer-Tropsch Co-Catalysts—A Mini-Review
by Erling Rytter and Anders Holmen
Catalysts 2015, 5(2), 478-499; https://doi.org/10.3390/catal5020478 - 26 Mar 2015
Cited by 112 | Viewed by 13320
Abstract
Deactivation of commercially relevant cobalt catalysts for Low Temperature Fischer-Tropsch (LTFT) synthesis is discussed with a focus on the two main long-term deactivation mechanisms proposed: Carbon deposits covering the catalytic surface and re-oxidation of the cobalt metal. There is a great variety in [...] Read more.
Deactivation of commercially relevant cobalt catalysts for Low Temperature Fischer-Tropsch (LTFT) synthesis is discussed with a focus on the two main long-term deactivation mechanisms proposed: Carbon deposits covering the catalytic surface and re-oxidation of the cobalt metal. There is a great variety in commercial, demonstration or pilot LTFT operations in terms of reactor systems employed, catalyst formulations and process conditions. Lack of sufficient data makes it difficult to correlate the deactivation mechanism with the actual process and catalyst design. It is well known that long term catalyst deactivation is sensitive to the conditions the actual catalyst experiences in the reactor. Therefore, great care should be taken during start-up, shutdown and upsets to monitor and control process variables such as reactant concentrations, pressure and temperature which greatly affect deactivation mechanism and rate. Nevertheless, evidence so far shows that carbon deposition is the main long-term deactivation mechanism for most LTFT operations. It is intriguing that some reports indicate a low deactivation rate for multi-channel micro-reactors. In situ rejuvenation and regeneration of Co catalysts are economically necessary for extending their life to several years. The review covers information from open sources, but with a particular focus on patent literature. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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6228 KiB  
Review
Heterogeneous Catalyst Deactivation and Regeneration: A Review
by Morris D. Argyle and Calvin H. Bartholomew
Catalysts 2015, 5(1), 145-269; https://doi.org/10.3390/catal5010145 - 26 Feb 2015
Cited by 1204 | Viewed by 89997
Abstract
Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid [...] Read more.
Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing). The key features and considerations for each of these deactivation types is reviewed in detail with reference to the latest literature reports in these areas. Two case studies on the deactivation mechanisms of catalysts used for cobalt Fischer-Tropsch and selective catalytic reduction are considered to provide additional depth in the topics of sintering, coking, poisoning, and fouling. Regeneration considerations and options are also briefly discussed for each deactivation mechanism. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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2591 KiB  
Review
Deactivation Pattern of a “Model” Ni/MgO Catalyst in the Pre-Reforming of n-Hexane
by Giuseppe Trunfio and Francesco Arena
Catalysts 2014, 4(2), 196-214; https://doi.org/10.3390/catal4020196 - 19 Jun 2014
Cited by 8 | Viewed by 6682
Abstract
The deactivation pattern of a “model” Ni/MgO catalyst in the pre-reforming of n-hexane with steam (T, 450 °C; P, 5–15 bar) is reviewed. The influence of the steam-to-carbon ratio (S/C, 1.5–3.5) on the rate of catalyst fouling by coking [...] Read more.
The deactivation pattern of a “model” Ni/MgO catalyst in the pre-reforming of n-hexane with steam (T, 450 °C; P, 5–15 bar) is reviewed. The influence of the steam-to-carbon ratio (S/C, 1.5–3.5) on the rate of catalyst fouling by coking is ascertained. Catalyst fouling leads to an exponential decay in activity, denoting 1st-order dependence of the coking process on active sites availability. Hydrogen hinders the coking process, though slight activity decay is due to sintering of the active Ni phase. Deactivation by thiophene causes a sharp, almost linear, drop to nearly zero activity within only 6 h; this deactivation is likely due to dissociative adsorption of thiophene with subsequent strong, irreversible chemical adsorption of S-atoms on active Ni sites, i.e., irreversible poisoning. Modeling of activity decay curves (α, at/a0) by proper kinetic equations allows assessing the effects of temperature, pressure, S/C, H2 and thiophene feed on the deactivation pattern of the model Ni/MgO catalyst by coking, sintering, and poisoning phenomena. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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1826 KiB  
Review
Influence of Reduction Promoters on Stability of Cobalt/g-Alumina Fischer-Tropsch Synthesis Catalysts
by Gary Jacobs, Wenping Ma and Burtron H. Davis
Catalysts 2014, 4(1), 49-76; https://doi.org/10.3390/catal4010049 - 11 Mar 2014
Cited by 48 | Viewed by 10084
Abstract
This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the [...] Read more.
This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing surface Co0 site densities (e.g., in research catalysts), ultra-small crystallites (e.g., <2–4.4 nm) formed are more susceptible to oxidation at high conversion relative to larger ones. The choice of promoter is important, as certain metals (e.g., Au) that promote cobalt oxide reduction can separate from cobalt during oxidation-reduction (regeneration) cycles. Finally, some elements have been identified to promote reduction but either poison the surface of Co0 (e.g., Cu), or produce excessive light gas selectivity (e.g., Cu and Pd, or Au at high loading). Computational studies indicate that certain promoters may inhibit polymeric C formation by hindering C-C coupling. Full article
(This article belongs to the Special Issue Advances in Catalyst Deactivation)
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