Mechanism-dependent on the different CeO 2 supports of phosphotungstic acid modification CeO 2 catalysts for the selective catalytic reduction of NO with NH 3

Song, Zhongxian; Zhang, Qiulin; Ma, Yangmin; Liu, Qixian; Ning, Ping; Liu, Xin; Wang, Jing; Zhao, Bin; Huang, Jianhong; Huang, Zhenzhen

doi:10.1016/j.jtice.2016.12.025

Cited by 15 publications

(6 citation statements)

References 40 publications

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“…Their results suggested that the SCR activity of heteropolyacid-promoted catalysts is much higher than that of ordinary SCR catalysts. Additionally, many reports have shown that the CeO 2 /H 3 PW 12 O 40 catalyst has enhanced SCR activity and SO 2 poisoning resistance because SO 2 cannot gain access into the secondary structure, but NO x molecules can enter the structure [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst

Zhang

Liu

et al. 2018

Catal Lett

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Heteropolyacids and their salts have been effectively used in selective catalytic reduction because of the Keggin structure and extraordinarily strong acidity. Catalysts with and without the Keggin structure were synthesized to further investigate the effects of heteropolyoxometallate on low temperature NH 3 -SCR. XRD, BET, Raman, H 2 -TPR, NH 3 -TPD, FT-IR, and SO 2 -TPD techniques were used to characterize the physicochemical characteristics of the catalysts. Results indicate that catalysts with the Keggin structure had more surface Brönsted and Lewis acid sites, and these catalysts had significantly improved performances in the SCR reaction and in SO 2 poisoning resistance. Graphical AbstractKeywords SCR catalyst · Ammonium heteropolyacid salt · Keggin structure Rui Wu and Ningqiang Zhang have contributed equally.

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Section: Introductionmentioning

confidence: 99%

The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst

Zhang

Liu

et al. 2018

Catal Lett

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“…However, this catalyst shows a poor performance that may be due to low surface area, low dispersion of the tungsten species, and uncontrolled synthesis method. In other studies, Song et al [26] and Geng et al [22] described the higher performance of ceria grafted HPW which the authors claimed to be related to better NH 3 adsorption. Nevertheless, for these systems, the active species controlling the activity are not precisely determined.…”

Section: Introductionmentioning

confidence: 91%

NH3-Selective Catalytic Reduction of NOx to N2 over Ceria Supported WOx Based Catalysts: Influence of Tungsten Content

et al. 2021

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A series of HPW/CeO2 catalysts generated from 12-tungstophosphoric acid, H3PW12O40 (HPW), supported on ceria and presenting different tungsten loadings (2, 4.5, 9, 16, and 40 wt% W) were prepared and characterized by N2 physisorption, XRD, IR, Raman, and UV-Vis. The different characterization techniques suggested that low loading of tungsten resulted in mainly isolated sites, while high tungsten loading produced polymeric or tungsten clusters. Those materials exhibited high activity in NH3-SCR of NOx into N2. Moreover, the series of experiments indicated that low loading in tungsten (2% HPW/CeO2) displayed the highest activity with a remarkable N2 selectivity (99%) at medium-high temperature (300–515 °C), owing to the high amount of monomeric tungstate coverage on the catalyst surface.

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“…As seen in Figure 2A, there were six bands: 1211, 1391, 1454, 1596, 1685, and 1737 cm −1 . The peaks centered at 1454 cm −1 and in the range of 1750-1650 cm −1 can be, respectively, attributed to asymmetric and symmetric bending (δ as and δ s ) vibrations of NH 4 + species on Brönsted acid sites [15][16][17].…”

Section: Catalytic Activitymentioning

confidence: 97%

DRIFT Study on Promotion Effect of the Keggin Structure over V2O5-MoO3/TiO2 Catalysts for Low Temperature NH3-SCR Reaction

Zhang

et al. 2018

Catalysts

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Abstract:Heteropoly acids (HPAs) with the Keggin structure have been widely used in NO x removal. Two kinds of catalysts (those with and without the Keggin structure) are prepared for studying the effect of the Keggin structure on the NH 3 -SCR reaction. A series of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) analyses are conducted to investigate the surface-adsorbed species on the catalysts during the SCR reaction. The mechanism for enhancing low-temperature activity of the catalysts is proposed. Furthermore, the effect of NH 4 + in the Keggin structure is also investigated. Results indicate that both the Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms occurred in the NH 3 -SCR reaction over the catalyst with the Keggin structure (Cat-A); in addition, when more acid sites are provided, NO x species activity is improved and more NH 4 + ions participate in reaction over Cat-A, thus promoting SCR activity.

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Mechanism-dependent on the different CeO 2 supports of phosphotungstic acid modification CeO 2 catalysts for the selective catalytic reduction of NO with NH 3

Cited by 15 publications

References 40 publications

The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst

The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst

NH3-Selective Catalytic Reduction of NOx to N2 over Ceria Supported WOx Based Catalysts: Influence of Tungsten Content

DRIFT Study on Promotion Effect of the Keggin Structure over V2O5-MoO3/TiO2 Catalysts for Low Temperature NH3-SCR Reaction

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