Effect of postsynthesis preparation procedure on the state of copper in CuBEA zeolites and its catalytic properties in SCR of NO with NH3

Baran, Rafał; Averseng, Frédéric; Wierzbicki, Dominik; Chałupka, Karolina; Krafft, Jean‐Marc; Grzybek, Teresa; Dźwigaj, Stanisław

doi:10.1016/j.apcata.2016.06.008

Cited by 18 publications

(9 citation statements)

References 62 publications

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“…It possesses pores larger than those of ZSM-5 with 12-memeberd ring openings (0.75 by 0.57 nm for linear and 0.65 by 0.56 nm for tortuous channels). BEA zeolite was tested as a support of catalytically active phases [35][36][37][38][39], including the total oxidation of VOCs [13-15, 20-21, 40]. In the latter case, a majority of research was done for noble-metal systems.…”

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confidence: 99%

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Rokicińska

Drozdek

Dudek

et al. 2017

Applied Catalysis B: Environmental

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GRAPHICAL ABSTRACT Highlights-Controlled amounts of cobalt were homogeneously introduced in BEA structure.-Various forms of Co species were identified in Co-containing BEA structure.-After saturation of framework sites Co formed oxide clusters and crystallites.-The presence of Lewis acid sites resulted in enhanced selectivity to CO and benzene.-The highest activity showed Co-containing SiBEA with dominant contribution of Co3O4. AbstractCo-containing HAlBEA zeolite was obtained by conventional wet impregnation of HAlBEA zeolite with an aqueous Co(NO3)2 . 6 H2O solution, whereas Co-containing SiBEA zeolites were prepared by a two-step post-synthesis method. This approach consists of, in the first step, dealumination of parent BEA zeolite to obtain an aluminum-free SiBEA support and then, in the subsequent step, contact of the obtained material with an aqueous solution of cobalt nitrate. As shown by X-ray diffraction and low-temperature N2 adsorption, the dealumination of BEA zeolite and introduction of cobalt ions did not involve destruction of zeolite structure, and only insignificant blocking of pore system was observed after introduction of high amounts of cobalt. Nevertheless, clear changes in acidity were found by FTIR of pre-adsorbed pyridine after dealumination of parent BEA zeolite and introduction of cobalt ions. The presence of Lewis acid sites resulted in enhanced selectivity to CO and benzene formed as by-products in the toluene combustion. Therefore, SiBEA zeolite was chosen as a support for an introduction of various amounts of Co into the zeolite structure (the intended Co contents of 3.0 -9.0 wt %). Depended on the amount of the introduced Co, cobalt was incorporated into the framework of BEA zeolite as isolated mononuclear Co(II) species, small Co(II) oxide clusters and/or Co3O4 crystallites distributed in the whole zeolite structure.The chemical environment and dispersion of cobalt species were studied by transmission electron microscopy (TEM), FTIR of pre-adsorbed NO, UV-vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy (XPS). Temperature-programmed reduction of hydrogen (H2-TPR) was also performed to determine reducibility of the Cocontaining SiBEA zeolites. It was confirmed that siliceous SiBEA zeolite was the excellent support of Co3O4, which was in turn recognized as the main active phase in the total oxidation of toluene. The best catalytic performance was achieved over the catalysts containing at least 0.05 mmol of Co in the form of Co3O4 per 1 g of SiBEA zeolite.

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confidence: 99%

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Rokicińska

Drozdek

Dudek

et al. 2017

Applied Catalysis B: Environmental

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“…When the temperature was 500 °C, the NOx conversion rate of Cu (4.2%) was below 85%, while the NOx conversion rates for Cu (3.4%), Cu (2.9%), and Cu (2.4%) were still over 90%. The state of copper played an important role in the SCR catalyst . Thus, the higher the copper content in the Cu-SSZ-13 catalyst, the worse was the thermal stability of the catalyst.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The state of copper played an important role in the SCR catalyst. 39 Thus, the higher the copper content in the Cu-SSZ-13 catalyst, the worse was the thermal stability of the catalyst.…”

Section: Resultsmentioning

confidence: 99%

Effects of Catalyst Physicochemical Properties on the Catalytic Activity of Cu Zeolite Selective Catalytic Reduction at Different Inlet Gas Conditions

Tan

Yin

et al. 2021

Energy Fuels

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Selective catalytic reduction (SCR) systems are important technical means of mitigating NOx emissions for diesel engines. The major challenge of this technique is to improve the low-temperature activity of the catalyst during engine cold start and the thermal stability on repeated exposure to high-temperature exhaust. A two-stage SCR system with a Cu-SSZ-13 catalyst was analyzed with SCR sample experiments and NH3 oxidation experiments. The effects of copper content, doping metals, structural arrangement, NO2/NOx ratio, and NH3/NOx ratio (ANR) on the NOx conversion reaction at different temperatures were investigated. Furthermore, the Cu-SSZ-13 catalyst activity was characterized by Fourier transform infrared spectroscopy, H2 temperature-programmed reduction, and X-ray diffraction. The results showed that the low-temperature catalytic performance first increased with increasing copper content and decreased with a further increase. The optimal value of copper content was around 3.4%. The thermal stability of Cu-SSZ-13 catalysts decreased with the increase in the copper content. The temperature window of the high NOx conversion rate was widened by doping Zr/Mn/Ce, and the temperature window was widened by 15.1–33.1%. The two-stage SCR system was compared with a single SCR, which showed that the NH3 oxidation rate increased by 46.9–88.7%, the NOx conversion rate increased by 67.7–85.5%, and T90 was optimized by 3.3–13.5% during engine cold start. This made the total NOx conversion rate to maintain a high level above 80% at temperatures over 500 °C. An appropriate NO2/NOx ratio and ANR could improve the NOx conversion rate at a low-temperature range.

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“…This is a well-established technique for probing Brønsted and Lewis acid sites in inorganic catalysts. 19 It was also recently applied to MOFs. 20,21 We used it here to identify the formation of Lewis acid sites at the ZrUC in the dehydrated defective materials of the UiO-x-0 series i.e.…”

Section: Infrared Spectroscopy Of Adsorbed Co (Used As a Basic Probe)mentioning

confidence: 99%

On the importance of combining bulk- and surface-active sites to maximize the catalytic activity of metal–organic frameworks for the oxidative dehydrogenation of alcohols using alkyl hydroperoxides as hydride acceptors

Gairola

Millot

Krafft

et al. 2020

Catal. Sci. Technol.

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Effect of postsynthesis preparation procedure on the state of copper in CuBEA zeolites and its catalytic properties in SCR of NO with NH3

Cited by 18 publications

References 62 publications

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Cobalt-containing BEA zeolite for catalytic combustion of toluene

Effects of Catalyst Physicochemical Properties on the Catalytic Activity of Cu Zeolite Selective Catalytic Reduction at Different Inlet Gas Conditions

On the importance of combining bulk- and surface-active sites to maximize the catalytic activity of metal–organic frameworks for the oxidative dehydrogenation of alcohols using alkyl hydroperoxides as hydride acceptors

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