Ce and Zr Modified WO3-TiO2 Catalysts for Selective Catalytic Reduction of NOx by NH3

Zhao, Wenyi; Li, Zhaoqiang; Wang, Yan; Fan, Rongrong; Zhang, Cheng; Wang, Yu; Guo, Xin; Wang, Rong; Zhang, Shule

doi:10.3390/catal8090375

Cited by 14 publications

(9 citation statements)

References 30 publications

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“…In addition to the above multiplex oxide catalysts, many research papers have reported that CeO 2 was combined with other transition metal oxides to form NH 3 -SCR catalysts, such as Sn 2 O 5 [102], VO x [103], CuO [104], Nb 2 O 5 [105], ZrO 2 [106] and CoO [107]. They can simultaneously enhance the surface acidity, redox performance and SO 2 /H 2 O resistance of the SCR catalysts.…”

Section: Other Cerium-based Multiplex Oxide Catalystsmentioning

confidence: 99%

Preparation and Performance of Cerium-Based Catalysts for Selective Catalytic Reduction of Nitrogen Oxides: A Critical Review

et al. 2021

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Selective catalytic reduction of nitrogen oxides with NH3 (NH3-SCR) is still the most commonly used control technology for nitrogen oxides emission. Specifically, the application of rare earth materials has become more and more extensive. CeO2 was widely developed in NH3-SCR reaction due to its good redox performance, proper surface acidity and abundant resource reserves. Therefore, a large number of papers in the literature have described the research of cerium-based catalysts. This review critically summarized the development of the different components of cerium-based catalysts, and characterized the preparation methods, the catalytic performance and reaction mechanisms of the cerium-based catalysts for NH3-SCR. The purpose of this review is to highlight: (1) the modification effect of the various metal elements for cerium-based catalysts; (2) various synthesis methods of the cerium-based catalysts; and (3) the physicochemical properties of the various catalysts and clarify their relations to catalytic performances, particularly in the presence of SO2 and H2O. Finally, we hope that this work can give timely technical guidance and valuable insights for the applications of NH3-SCR in the field of NOx control.

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Section: Other Cerium-based Multiplex Oxide Catalystsmentioning

confidence: 99%

Preparation and Performance of Cerium-Based Catalysts for Selective Catalytic Reduction of Nitrogen Oxides: A Critical Review

et al. 2021

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“…The results for steady-state activity of catalysts were recorded after about 20 min at each temperature. The NOx conversion were calculated accordingly [3], whereas NOx = NO + NO 2 .…”

Section: Activity Evaluationmentioning

confidence: 99%

“…Selective catalytic reduction with ammonia (NH 3 -SCR) has been successfully developed as a promising technology for reducing NOx emitted in combustion gas emissions from automotive sources [1][2][3]. Cu-SSZ-13, with superior activity and durability, has been generally considered as the predominant commercial SCR catalyst applied in North American, European and Chinese diesel vehicles [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Deactivation and Regeneration for the SO2-Poisoning of a Cu-SSZ-13 Catalyst in the NH3-SCR Reaction

Wang

Fan

et al. 2019

Catalysts

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Cu-SSZ-13 has been generally considered as the predominant commercial selective catalytic reduction (SCR) catalyst in the NH3-SCR reaction because of its superior activity and durability. However, in real applications, SCR catalysts readily undergo hydrothermal aging and sulfur poisoning. In this work, the deactivation and regeneration of a commercial Cu-SSZ-13 catalyst was investigated for SO2 exposures during hydrothermal aging and the effect of different regeneration temperatures was compared. By using XRD, SEM, H2-temperature programmed reduction (TPR), X–ray photoelectron spectra (XPS) and NH3-temperature programmed desorption (TPD) analysis, it was found that SO2 poisoning influenced the chabazite (CHA) structure even if regeneration cannot restore its original structure, the redox ability and ammonia storage performance also influenced by sulfation and the regeneration process. Moreover, the extent of a decrease in redox ability was more severe than acidity, suggesting that the amount of isolated Cu2+ and Cu+ reduction was responsible for irreversible deactivation over the Cu-SSZ-13 catalyst. Combined with the analysis of Ea values and pre-exponential factor of the SCR reaction, a more likely explanation for the irreversible deactivation was that active sites were lost mostly in sulfated and regenerated process sites.

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“…Recently, Ce-containing catalysts have attracted a lot of attention for their superior de-NO X activities that are caused by their unique oxygen storage properties [11][12][13][14][15]. Cao et al [16] prepared a CeO 2 /TiO 2 catalyst with high SCR activity due to enhanced "fast SCR" reactions following the L-H mechanism.…”

Section: Introductionmentioning

confidence: 99%

In Situ DRIFTS Investigation on CeOx Catalyst Supported by Fly-Ash-Made Porous Cordierite Ceramics for Low-Temperature NH3-SCR of NOX

Wang

Chen

et al. 2019

Catalysts

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A series of CeOx catalysts supported by commercial porous cordierite ceramics (CPCC) and synthesized porous cordierite ceramics (SPCC) from fly ash were prepared for selective catalytic reduction of NOx with ammonia (NH3-SCR). A greater than 90% NOx conversion rate was achieved by the SPCC supported catalyst at 250–300 °C when the concentration of loading precursor was 0.6 mol/L (denoted as 0.6Ce/SPCC), which is more advantageous than the CPCC supported ones. The EDS mapping results reveal the existence of evenly distributed impurities on the surface of SPCC, which hence might be able to provide more attachment sites for CeOx particles. Further measurements with temperature programmed reduction by hydrogen (H2-TPR) demonstrate more reducible species on the surface of 0.6Ce/SPCC, thus giving rise to better NH3-SCR performance at a low-temperature range. The X-ray photoelectron spectroscopy (XPS) analyses reveal that the Ce atom ratio is higher in 0.6Ce/SPCC, indicating that a higher concentration of catalytic active sites could be found on the surface of 0.6Ce/SPCC. The in situ diffused reflectance infrared fourier transform spectroscopy (DRIFTS) results indicate that the SCR reactions over 0.6Ce/SPCC follow both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. Hence, the SPCC might be a promising candidate to provide support for NH3-SCR catalysts, which also provide a valuable approach to recycling the fly ash.

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Ce and Zr Modified WO3-TiO2 Catalysts for Selective Catalytic Reduction of NOx by NH3

Cited by 14 publications

References 30 publications

Preparation and Performance of Cerium-Based Catalysts for Selective Catalytic Reduction of Nitrogen Oxides: A Critical Review

Preparation and Performance of Cerium-Based Catalysts for Selective Catalytic Reduction of Nitrogen Oxides: A Critical Review

Deactivation and Regeneration for the SO2-Poisoning of a Cu-SSZ-13 Catalyst in the NH3-SCR Reaction

In Situ DRIFTS Investigation on CeOx Catalyst Supported by Fly-Ash-Made Porous Cordierite Ceramics for Low-Temperature NH3-SCR of NOX

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