Intensification studies of heterogeneous catalysts: probing and overcoming catalyst deactivation during liquid phase operation

Hammond, Ceri

doi:10.1039/c7gc00163k

Cited by 77 publications

(105 citation statements)

References 108 publications

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“…When talking about stability, however, it is often more appropriate to compare the performance of different catalysts against substrate turnover number (indicative of the quantity of substrate that has passed over the catalytic bed). In fact, it is often more important to evaluate the catalyst stability as a function of the number of reactant molecules that have been processed rather than the time on stream, particularly if disparate levels of activity are observed between catalytic materials [15]. Therefore, the relative performances of the catalysts were also compared as function of substrate turnovers (Eq.…”

Section: Effect Of Metal Loading Of Post-synthetic Materialsmentioning

confidence: 99%

“…The outstanding catalytic ability of Sn-Beta for carbohydrate valorisation has sparked interest for its possible utilisation on commercial scale. However, despite its excellent catalytic performance for glucose isomerisation [10,11] and methyl lactate production [12,13], until recently little information on its stability was available, even though the lifetime of a catalyst represents one of its most important features [14][15][16]. In fact, only recently have researchers started to investigate the stability of this catalyst for the continuous isomerisation of sugarbased molecules [17].…”

Section: Introductionmentioning

confidence: 99%

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Influence of Composition and Preparation Method on the Continuous Performance of Sn-Beta for Glucose-Fructose Isomerisation

et al. 2018

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The stability, activity and selectivity of various Sn-Beta catalysts are investigated to identify how the composition of the catalyst, in addition to its method of preparation, impact its ability to continuously isomerise glucose to fructose. Increasing the Sn loading in post-synthetically prepared catalysts leads to a decrease of both activity and stability. Accordingly, materials containing dilute amounts of Sn appear to be most suitable for continuous operation. Furthermore, the method of preparation has a profound impact on the overall performance of the catalyst. In fact, preparation of Sn-Beta by hydrothermal synthesis results in improvements of both activity and stability, with respect to the post-synthetic preparation of an otherwise-analogous material. The improved resistance of hydrothermal Sn-Beta is attributed, through a combination of operando UV-Vis, TPD-MS and vapour adsorption isotherms, to its greater resistance to deactivation by methanol (the reaction solvent). Complementary 119 Sn CPMG MAS NMR experiments also indicate the presence of different Sn sites in the hydrothermal material, which, alongside the presence of a less adsorptive siliceous matrix, may be intrinsically less prone to solvent interaction than those present in post-synthetic Sn-Beta.

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Section: Effect Of Metal Loading Of Post-synthetic Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Composition and Preparation Method on the Continuous Performance of Sn-Beta for Glucose-Fructose Isomerisation

et al. 2018

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“…[18][19][20] Possessing an ability to operate continuously, without exhibiting excessive levels of deactivation, is one of the most important properties a promising heterogeneous catalyst must exhibit, in order to be suitable for industrialization. 21,22 As such, study and optimization of the stability of the catalyst under continuous conditions is paramount. In contrast to fossil feedstock, the highly oxygenated nature of sugar-based substrates necessitates processing in the liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Active Site Hydration Governs the Stability of Sn-Beta during Continuous Glucose Conversion

2018

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The stability of Sn-Beta for the continuous upgrading of hexoses is improved dramatically upon the addition of small amounts of water to the methanol/sugar reaction feed, despite water itself being an unfavourable solvent. Herein, the molecular level origin of this effect is investigated. Spectroscopic studies of the catalytic materials pre-, post-and during operation, with operando UV-Vis, 119 Sn CPMG MAS NMR, DRIFTS-MS, TGA, TPD/O-MS and porosimetry, are coupled to additional kinetic studies, to generate detailed structure-activity-lifetime relationships. In doing so, we find that the addition of water influences two particular processesfouling and active site modification. However, mitigating the second is the most crucial role of water. Indeed, in the absence of water, the loss of Sn-OH and Si-OH sites occurs. Notably, these changes in active site hydration correlate to deactivation and reactivation of the system. The consequences of these findings, both for mechanistic understanding of the system in addition to the design of alternative regeneration methods, are also discussed.

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“…A review, published by Zhang and co‐workers, provides a comprehensive overview of the transformation of cellulose to polyols with a short section on catalyst recycling . A further study describes, among other things, problems with the catalyst stability in the conversion of biomass …”

Section: Introductionmentioning

confidence: 99%

“…[33] Af urther study describes, among other things,p roblems with the catalyst stability in the conversion of biomass. [36] In search of tungsten compounds that are stable under hydrothermal conditions, references to zirconium tungsten oxideswere found. In the literature, under hydrothermal conditions, produced tungsten and zirconia containing materialc an be found.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermally Stable Ruthenium–Zirconium–Tungsten Catalyst for Cellulose Hydrogenolysis to Polyols

2017

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In this work, we describe a catalytic material based on a zirconium–tungsten oxide with ruthenium for the hydrogenolysis of microcrystalline cellulose under hydrothermal conditions. With these catalysts, polyols can be produced with high yields. High and stable polyol yields were also achieved in recycling tests. A catalyst with 4.5 wt % ruthenium in total achieved a carbon efficiency of almost 100 %. The prepared Zr‐W oxide is mesoporous and largely stable under hydrothermal conditions (493 K and 65 bar hydrogen). Decomposition into the components ZrO2 and WO3 could be observed at temperatures of 1050 K in air.

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Intensification studies of heterogeneous catalysts: probing and overcoming catalyst deactivation during liquid phase operation

Abstract: In addition to high levels of activity and selectivity, promising heterogeneous catalysts must also possess sufficient levels of stability. This tutorial review covers the topic of heterogeneous catalyst deactivation during liquid phase operation.

Cited by 77 publications

References 108 publications

Influence of Composition and Preparation Method on the Continuous Performance of Sn-Beta for Glucose-Fructose Isomerisation

Influence of Composition and Preparation Method on the Continuous Performance of Sn-Beta for Glucose-Fructose Isomerisation

Active Site Hydration Governs the Stability of Sn-Beta during Continuous Glucose Conversion

Hydrothermally Stable Ruthenium–Zirconium–Tungsten Catalyst for Cellulose Hydrogenolysis to Polyols

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