A molecular view of heterogeneous catalysis

Christensen, Claus H.; Nørskov, Jens K.

doi:10.1063/1.2839299

Cited by 120 publications

(77 citation statements)

References 65 publications

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“…Each sample consisted of between 5 and 10 saturated catalyst pellets so as to provide a well-averaged measurement of the surfaceadsorbate interactions present between the imbibed liquids and the pore surfaces present throughout each oxide support. 1 H NMR spin-lattice relaxation measurements were performed using a Bruker DMX 300 spectrometer with a 1 H operational frequency of 300.13 MHz. All measurements were performed under ambient pressure at 20 ± 0.2 °C.…”

Section: Nmr Measurementsmentioning

confidence: 99%

Exploring catalyst passivation with NMR relaxation

2017

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NMR relaxation has recently emerged as a novel and non-invasive tool for probing the surface dynamics of adsorbate molecules within liquid-saturated mesoporous catalysts. The elucidation of such dynamics is of particular relevance to the study and development of solvated green catalytic processes, such as the production of chemicals and fuels from bio-resources. In this paper we develop and implement a protocol using high field 1 H NMR spin-lattice relaxation as a probe of the reorientational dynamics of liquids imbibed within mesoporous oxide materials. The observed relaxation of liquids within mesoporous materials is highly sensitive to the adsorbed surface layer, giving insight into tumbling behaviour of spin-bearing chemical environments at the pore surface. As a prototypical example of relevance to liquid-phase catalytic systems, we examine the mobility of liquid methanol within a range of common catalyst supports. In particular, through the calculation and comparison of a suitable interaction parameter, we assess and quantify changes to these surface dynamics upon replacing surface hydroxyl groups with hydrophobic alkyl chains. Our results indicate that the molecular tumbling of adsorbed methanol is enhanced upon surface passivation due to the suppression of surface-adsorbate hydrogen bonding interactions, and tends towards that of the unrestricted bulk liquid. A complex analysis in which we account for the influence of changing pore structure and surface chemistry upon passivation is discussed. The results presented highlight the use of NMR spin-lattice relaxation measurements as a non-invasive probe of molecular dynamics at surfaces of interest to liquidphase heterogeneous catalysis.3

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Section: Nmr Measurementsmentioning

confidence: 99%

Exploring catalyst passivation with NMR relaxation

2017

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“…His contributions to the theories of surface chemical bonding and catalytic reaction over the past 30 years lead to a giant leap forward in our molecular level understanding of surface chemistry and heterogeneous catalysis [12][13][14][15][16][17][18][19][20][21]. Of course, his achievement is a result of his exceptional expertise in theoretical chemistry, but, from the point of view of an experimentalist, the more important factors perhaps are his willingness to work closely with experimentalists and his ability to grasp the essence of experimental development [22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Major Successes of Theory-and-Experiment-Combined Studies in Surface Chemistry and Heterogeneous Catalysis

Somorjai

2010

Top Catal

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Experimental discoveries followed by theoretical interpretations that pave the way of further advances by experimentalists is a developing pattern in modern surface chemistry and catalysis. The revolution of modern surface science started with the development of surfacesensitive techniques such as LEED, XPS, AES, ISS and SIMS, in which the close collaboration between experimentalists and theorists led to the quantitative determination of surface structure and composition. The experimental discovery of the chemical activity of surface defects and the trends in the reactivity of transitional metals followed by the explanations from the theoretical studies led to the molecular level understanding of active sites in catalysis. The molecular level knowledge, in turn, provided a guide for experiments to search for new generation of catalysts. These and many other examples of successes in experiment-and-theory-combined studies demonstrate the importance of the collaboration between experimentalists and theorists in the development of modern surface science.

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“…Identification of the active catalytic sites needs to be done for rational catalyst design. 83 Detailed characterization under ambient (ex situ) and under reaction conditions (in situ) allow us to qualitatively derive ''structure-function'' relationships. More comprehensive texts about characterization techniques for a host of catalytic materials and applications can be found elsewhere.…”

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confidence: 99%

The critical role of heterogeneous catalysis in lignocellulosic biomass conversion

Lin

Huber

2009

Energy Environ. Sci.

426

256

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Lignocellulosic biofuels have a tremendous potential to reduce problems caused by our dependence on fossil fuels. The current roadblock with biofuels is the lack of economical conversion technologies. Heterogeneous catalysis offers immense potential in helping to make lignocellulosic biofuels a commercial reality. In this article we discuss the central role of heterogeneous catalysis in biomass conversion. We review the science of catalysis and the different routes to make biofuels. During the last several decades multiple new spectroscopic, theoretical, and synthesis tools are available that allow us to study catalysis at a molecular level. These new tools will allow us to rapidly develop new catalytic processes for the production of cost-efficient lignocellulosic biofuels.

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A molecular view of heterogeneous catalysis

Cited by 120 publications

References 65 publications

Exploring catalyst passivation with NMR relaxation

Exploring catalyst passivation with NMR relaxation

Major Successes of Theory-and-Experiment-Combined Studies in Surface Chemistry and Heterogeneous Catalysis

The critical role of heterogeneous catalysis in lignocellulosic biomass conversion

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