Low-temperature CO oxidation on Ag/ZSM-5 catalysts: Influence of Si/Al ratio and redox pretreatments on formation of silver active sites

Kolobova, Ekaterina; Pestryakov, Alexey; Mamontov, G. V.; Kotolevich, Yulia; Bogdanchikova, Nina; Farı́as, M.H.; Восмериков, А. В.; Восмерикова, Л. Н.; Corberán, Vicente Cortés

doi:10.1016/j.fuel.2016.10.037

Cited by 57 publications

(21 citation statements)

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“…These are directly related to the framework Al content, hence Al determination is often used to assess zeolite acidity. Several techniques can be used to determine the Si/Al ratio, yielding powder averaged information, for example, elemental analysis using inductive coupled plasma (ICP), magic angle spinning (MAS) 29 Si and 27 Al NMR, laser induced break down spectroscopy (LIBS), X‐ray photon electron spectroscopy (XPS) and time of flight‐secondary ion mass spectrometry (TOF‐SIMS) . All of these techniques lead to the determination of the ‘bulk“ scale acidity and some are even able to obtain single crystal information given that crystal sizes and aluminum content are sufficiently large; for example, single crystal X‐ray diffraction and energy dispersive X‐ray spectroscopy (EDX) coupled to electron microscopy potentially with focused‐ion‐beam milling .…”

Section: Figurementioning

confidence: 99%

“…Further, no information regarding site accessibility is obtained in these results. Direct measurements of acid site density and strength are possible via temperature programmed desorption (TPD) and infrared‐ or Raman spectroscopy using basic probe molecules such as pyridine . The last two techniques also have the added benefit to distinguish Lewis and Brønsted sites.…”

Section: Figurementioning

confidence: 99%

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Assessing Inter and Intra‐particle Heterogeneity in Alumina‐poor H‐ZSM‐5 Zeolites

et al. 2017

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We reveal the presence of significant variations in Brønsted catalytic activity within and between individual H-ZSM-5 zeolite crystals. Fluorescence microscopy in combinationw ith a fluorogenic probe was used to resolve the catalytic activity at the nanoscale. The observed variations in catalytic activity could be directly linked to structural parameters and crystal morphology observed in scanninge lectron microscopy and by specifically stainingc rystal defects. The obtained resultsa re directly comparedw ith ensemblea veraged information from techniques such as pyridine IR spectroscopy and nitrogen physisorption, typically used to characterize acid zeolites. The inter-and intra-particle heterogeneities resolved by the employed fluorescence approach remainu naddressed by bulk characterization. Our experimental resultsr elate the heterogeneous catalytic activity to variation in both the Si/Al ratio and mesoporosity inducedd uring the zeolite synthesis.The preparation of zeolite-based industrial catalysts usually involves mixingt he zeolitesw ith silicaa nd or aluminab inders in order to dilute the zeolite properties and to obtain the desired throughput. [1][2][3] During this process it is assumed that the zeolite crystalsthemselves are homogeneous in nature, [2,4,5] that is, only small variations in properties between the zeolite crystals in ab atch exist. However,i fthis assumption is wrong and large variations in, for example, acid site density are present, parts of the shaped catalystc ould become more active than others,r esulting in undesired coke formation and thus al oss in catalystactivity and lifetime. [4,6,7] Twop arameters impacting catalyst activity are the number and strength of acid sites present in az eolite. These are directly relatedt ot he framework Al content, [8,9] hence Al determination is often used to assess zeolite acidity.S everalt echniques can be used to determine the Si/Al ratio, yielding powder averaged information, for example, elemental analysisu sing inductive coupled plasma (ICP), [10,11] magic angle spinning (MAS) 29 Si and 27 Al NMR, [8,12] laser induced break down spectroscopy (LIBS), [13] X-ray photon electron spectroscopy (XPS) [12,14] and time of flight-secondary ion mass spectrometry (TOF-SIMS). [15,16] All of theset echniques lead to the determination of the 'bulk" scale acidity and some are even able to obtain single crystal information given that crystal sizes and aluminum content are sufficiently large; [17] for example, single crystal X-ray diffraction [17,18] and energy dispersive X-ray spectroscopy (EDX) coupled to electron microscopy potentially with focused-ion-beam milling. [14,19] In summary,t he acidic properties of zeolitesa re often deduced indirectly from the aluminum content.F urther,n oi nformation regarding site accessibility is obtained in these results. Direct measurements of acid site density and strengtha re possible via temperature programmed desorption (TPD) [8,14,20] and infrared- [2,21,22] or Raman spectroscopy [23] using basic probe molecules such...

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Assessing Inter and Intra‐particle Heterogeneity in Alumina‐poor H‐ZSM‐5 Zeolites

et al. 2017

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“…)52,53 suggesting the existence of oxidized Ag. The existence of the oxidized Ag can be underestimated by XPS performed in the vacuum environment, which would promote the reduction of the cation Ag.…”

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confidence: 99%

Soot oxidation performance with a HZSM-5 supported Ag nanoparticles catalyst and the characterization of Ag species

et al. 2017

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“…The quality of support toward CO oxidation was found to be dependent on various salient features such as porosity, productivity, selectivity and production cost along with reaction time, temperature and pressure [ 13 , 14 ]. Considering all of these aspects, developing noble metal-supported transition metals (metal oxides) such as [ 15 , 16 ] zeolite- [ 17 ] and clay-based [ 18 ] nano-catalysts will be of high significance to achieve CO oxidation in a controlled manner.…”

Section: Introductionmentioning

confidence: 99%

Noble Metal Nanoparticles Incorporated Siliceous TUD-1 Mesoporous Nano-Catalyst for Low-Temperature Oxidation of Carbon Monoxide

et al. 2020

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This report, for the first time, demonstrated the low-temperature oxidation of carbon monoxide (CO) using nano-catalysts consisting of noble metal nanoparticles incorporated in TUD-1 mesoporous silica nano-structures synthesized via a one-pot surfactant-free sol–gel synthesis methodology. Herein, we investigated a nano-catalyst, represented as M-TUD-1 (M = Rh, Pd, Pt and Au), which was prepared using a constant Si/M ratio of 100. The outcome of the analytical studies confirmed the formation of a nano-catalyst ranging from 5 to 10 nm wherein noble metal nanoparticles were distributed uniformly onto the mesopores of TUD-1. The catalytic performance of M-TUD-1 catalysts was examined in the environmentally impacted CO oxidation reaction to CO2. The catalytic performance of Au-TUD-1 benchmarked other M-TUD-1 catalysts and a total conversion of CO was obtained at 303 K. The activity of the other nano-catalysts was obtained as Pt-TUD-1 > Pd-TUD-1 > Rh-TUD-1, with a total CO conversion at temperatures of 308, 328 and 348 K, respectively. The Au-TUD-1 exhibited a high stability and reusability as indicated by the observed high activity after ten continuous runs without any treatment. The outcomes of this research suggested that M-TUD-1 are promising nano-catalysts for the removal of the toxic CO gas and can also potentially be useful to protect the environment where a long-life time, cost-effectiveness and industrial scaling-up are the key approaches.

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Low-temperature CO oxidation on Ag/ZSM-5 catalysts: Influence of Si/Al ratio and redox pretreatments on formation of silver active sites

Cited by 57 publications

References 53 publications

Assessing Inter and Intra‐particle Heterogeneity in Alumina‐poor H‐ZSM‐5 Zeolites

Assessing Inter and Intra‐particle Heterogeneity in Alumina‐poor H‐ZSM‐5 Zeolites

Soot oxidation performance with a HZSM-5 supported Ag nanoparticles catalyst and the characterization of Ag species

Noble Metal Nanoparticles Incorporated Siliceous TUD-1 Mesoporous Nano-Catalyst for Low-Temperature Oxidation of Carbon Monoxide

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