Turnover frequencies in metal catalysis: Meanings, functionalities and relationships

Spivey, James J.; Roberts, Gary L.; Goodwin, James G.; Kim, Soo Jeong; Rhodes, William D.

doi:10.1039/9781847553294-00320

Cited by 20 publications

(3 citation statements)

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“…The turnover frequency (TOF) value of [AuNPs] red /silica hex at 210 °C as a thin-film catalyst was calculated to be 0.02 min −1 , which is higher than that of [AuNPs] cal /silica hex at 250 °C with a value of 0.01 min −1 . Such catalytic activity of the AuNP–film catalyst prepared by thermal hydrogen reduction at 210 °C is due to its higher TOF value [48]. Moreover, in the same catalytic reduction of 4-NP, this TOF value is comparable to Au-Fe 3 O 4 as a bifunctional catalyst [49].…”

Section: Resultsmentioning

confidence: 99%

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

Jalani

Yuliati

Lee

et al. 2019

Beilstein J. Nanotechnol.

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We report that transparent mesostructured silica/gold nanocomposite materials with an interpore distance of 4.1 nm, as-synthesized from a templated sol–gel synthesis method using discotic trinuclear gold(I) pyrazolate complex, were successfully utilized for the fabrication of thin film mesoporous silica nanocomposites containing gold nanoparticles. The material exhibited a highly ordered hexagonal structure when subjected to a thermal hydrogen reduction treatment at 210 °C. In contrast, when the material was subjected to calcination as a heat treatment from 190 to 450 °C, the thin film nanocomposites showed an intense d 100 X-ray diffraction peak. Moreover, gold nanoparticles inside the thin film nanocomposites were confirmed by the presence of the d 111 diffraction peak at 2θ = 38.2°, a surface plasmon resonance peak between 500–580 nm, and the spherical shape observed in the transmission electron microscope images, as well as the visual change in color from pink to purple. Interestingly, by simply dipping the material into a reaction solution of 4-nitrophenol at room temperature, the highly ordered structure of the as-fabricated silica/gold nanoparticle thin film composite after thermal hydrogen reduction at 210 °C resulted in an improved catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol compared to the material calcined at 250 °C. Such catalytic activity is due to the presence of gold nanoparticles of smaller size in the silicate channels of the highly ordered mesoporous film nanocomposites.

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Section: Resultsmentioning

confidence: 99%

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

Jalani

Yuliati

Lee

et al. 2019

Beilstein J. Nanotechnol.

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“…The TOF is related to the consumed styrene oxide. [72][73][74][75] For styrene carbonate at 2 h reaction time, the variation was between 0.6 and 3.13% more yield when ZnCoCn was used as the reference, except for the ZnCoR material, which produced 9% more product. On the other hand, at 6 h, only the cubic phases achieved a similar StCO 3 yield and the blank that presented 7.4% less and the ZnCoRs generated only 56%, respecting ZnCoCn.…”

Section: Papermentioning

confidence: 99%

Unraveling the role of internal–external metal substitution in Zn₃[Co(CN₆)]₂ for the styrene oxide–CO₂ cycloaddition reaction

Del Angel-Gómez,

Reséndiz-Hernández,

Vega-Moreno

et al. 2024

Dalton Trans.

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“…TOF determines the intrinsic activity unbiased by the amount of catalyst used, and concentration of active sites. [43] However, determining TOF is not always successful since the catalytic active sites may differ from the surface sites measured by chemisorption. [44]…”

Section: Evaluation Parameters For Ec Co 2 Rrmentioning

confidence: 99%

Coordination Environment in Single‐Atom Catalysts for High‐Performance Electrocatalytic CO₂ Reduction

et al. 2022

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Climate change is nearing the "point of no return," the threshold year that will be too late to limit global warming. [1] Decreasing the greenhouse gas CO 2 is needed, either through reducing fossil fuel use and other CO 2 -producing activities or through converting CO 2 into different forms. The former is actively being pursued at the government level with alternative energy sources. However, natural fuels have their limitations. In the latter, there is CO 2 capture and storage, whether it is by turning CO 2 into calcium carbonate or by trapping it in oil and gas reservoirs. [2] While the two solutions are feasible for some countries, in small countries where there are few geological storage sites, the CO 2 needs to be transferred, which makes these methods less effective. Electrochemical carbon dioxide reduction reaction (EC CO 2 RR) does not hold the same dilemma as it produces CO, which can be mixed with H 2 to create syngas or high-value hydrocarbons. [3] One way to increase the specific product is to incorporate other metals, either by alloying or by metal decoration. [4] Another way is to modify the structure of the metal, either to increase the surface area using nanostructures and thus increase catalytic activity or to change the metal coordination. [5][6][7] A variety of nanostructured materials, starting from 2D nanosheets to quantum dots, [5] have been researched for use in catalytic applications. Morphology and facet engineering led to many successful kinds of research. However, the maximum atomic utilization can be realized by a newly emerging type of electrocatalyst, single-atom catalysts (SACs). [6] SACs not only enable 100% atom utilization but also show high catalytic activity due to a lowcoordination environment and more exposed active sites [7] and allow the use of metals with intrinsically low CO 2 conversion efficiency. [8] The reason for the high CO 2 RR faradaic efficiency (FE) is elaborated in Section 2.1. SACs are catalysts where the active site is in the form of isolated single atoms as opposed to clusters. The concept was first proposed in 2011 by Qiao et al. [9] and in 2015, Varela et al. [10] used single metal containing N-doped carbon catalysts (M-N-C catalysts) for CO 2 R to syngas; a mixture of H 2 and CO. These single atom sites are either supported by carbon-based structures or stabilized by alloying. [11] Unlike bulk or nanostructures, which can be characterized in a comparably simple manner, SACs are on the atomic scale and require high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) coupled with an energy-dispersive X-ray spectrometer (EDX) mapping for visual analysis of the dispersed metal atoms. The typical nonvisual analysis includes X-ray absorption near edge structure (XANES) and extended X-ray

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Turnover frequencies in metal catalysis: Meanings, functionalities and relationships

Cited by 20 publications

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Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

Unraveling the role of internal–external metal substitution in Zn₃[Co(CN₆)]₂ for the styrene oxide–CO₂ cycloaddition reaction

Coordination Environment in Single‐Atom Catalysts for High‐Performance Electrocatalytic CO₂ Reduction

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Turnover frequencies in metal catalysis: Meanings, functionalities and relationships

Cited by 20 publications

References 0 publications

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

Unraveling the role of internal–external metal substitution in Zn3[Co(CN6)]2 for the styrene oxide–CO2 cycloaddition reaction

Coordination Environment in Single‐Atom Catalysts for High‐Performance Electrocatalytic CO2 Reduction

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Unraveling the role of internal–external metal substitution in Zn₃[Co(CN₆)]₂ for the styrene oxide–CO₂ cycloaddition reaction

Coordination Environment in Single‐Atom Catalysts for High‐Performance Electrocatalytic CO₂ Reduction