Promotion effect of tungsten on the activity of Pt/HZSM-5 for H2-SCR

Zhang, Xiaoxiao; Wang, Xinping; Zhao, Xiaojuan; Xu, Yufan; Liu, Ye; Yu, Qing

doi:10.1016/j.cej.2014.09.030

Cited by 45 publications

(15 citation statements)

References 42 publications

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“…NO 2 and nitrate species are thought to be essential intermediates in the reaction [265]. However, other authors found that NO adsorption and decomposition on Pt would be the most important step of the reaction [268,269] [270]. Replacing Pt by Ru does not significantly improve the SCO reaction at lower temperatures [271], which does not allow selective conversion of ammonia formed in H 2 -SCR.…”

Section: Reduction By Hydrogen (H 2 -Scr)mentioning

confidence: 97%

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Tungsten-Based Catalysts for Environmental Applications

2021

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This review aims to give a general overview of the recent use of tungsten-based catalysts for wide environmental applications, with first some useful background information about tungsten oxides. Tungsten oxide materials exhibit suitable behaviors for surface reactions and catalysis such as acidic properties (mainly Brønsted sites), redox and adsorption properties (due to the presence of oxygen vacancies) and a photostimulation response under visible light (2.6–2.8 eV bandgap). Depending on the operating condition of the catalytic process, each of these behaviors is tunable by controlling structure and morphology (e.g., nanoplates, nanosheets, nanorods, nanowires, nanomesh, microflowers, hollow nanospheres) and/or interactions with other compounds such as conductors (carbon), semiconductors or other oxides (e.g., TiO2) and precious metals. WOx particles can be also dispersed on high specific surface area supports. Based on these behaviors, WO3-based catalysts were developed for numerous environmental applications. This review is divided into five main parts: structure of tungsten-based catalysts, acidity of supported tungsten oxide catalysts, WO3 catalysts for DeNOx applications, total oxidation of volatile organic compounds in gas phase and gas sensors and pollutant remediation in liquid phase (photocatalysis).

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Section: Reduction By Hydrogen (H 2 -Scr)mentioning

confidence: 97%

“…NO2 and nitrate species are thought to be essential intermediates in the reaction [265]. However, other authors found that NO adsorption and decomposition on Pt would be the most important step of the reaction [268,269]. Maximum NO conversion is observed between 90 and 130 °C.…”

Section: Reduction By Ethanol (C 2 H 5 Oh-scr)mentioning

confidence: 99%

Tungsten-Based Catalysts for Environmental Applications

2021

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“…Traditional carriers of catalyst for NO reduction include metal oxide (e.g., Al 2 O 3 [87], SiO 2 [88]), zeolite (ZSM-5 [89], ZIF [90], H-Zeolite Y(HY) [91]), aluminate spinel [92], and perovskite-type composite oxide [93]. They are relative stable and commonly compatible with most of precious and non-precious metals.…”

Section: Traditional Carriermentioning

confidence: 99%

“…However, when they coexist in the catalyst, the two synergistically occur preferentially. The synergistic effect of W and Pt not only facilitates the Pt to exhibit a metallic state in the catalyst, but also increases the dissociation speed of NO and H 2 on Pt while inhibiting the formation of nitrate [89]. Zhang et al [91] prepared Pt/HY catalyst by impregnation method, and the loading amounts of Pt were 0.1, 0.2, 0.5, and 1.0 wt.%.…”

Section: Traditional Carriermentioning

confidence: 99%

State-of-Art Review of NO Reduction Technologies by CO, CH4 and H2

et al. 2021

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Removal of nitrogen oxides during coal combustion is a subject of great concerns. The present study reviews the state-of-art catalysts for NO reduction by CO, CH4, and H2. In terms of NO reduction by CO and CH4, it focuses on the preparation methodologies and catalytic properties of noble metal catalysts and non-noble metal catalysts. In the technology of NO removal by H2, the NO removal performance of the noble metal catalyst is mainly discussed from the traditional carrier and the new carrier, such as Al2O3, ZSM-5, OMS-2, MOFs, perovskite oxide, etc. By adopting new preparation methodologies and introducing the secondary metal component, the catalysts supported by a traditional carrier could achieve a much higher activity. New carrier for catalyst design seems a promising aspect for improving the catalyst performance, i.e., catalytic activity and stability, in future. Moreover, mechanisms of catalytic NO reduction by these three agents are discussed in-depth. Through the critical review, it is found that the adsorption of NOx and the decomposition of NO are key steps in NO removal by CO, and the activation of the C-H bond in CH4 and H-H bonds in H2 serves as a rate determining step of the reaction of NO removal by CH4 and H2, respectively.

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“…Xue et al [208] directly deposited Pt with different content on MIL-96 (Al) surface by hydrothermal method. Pt was slightly loaded on MIL-96 (Al) surface and H 2 -SCR catalytic activity was excellent at 80 • C. Zhang et al [209] modified H 2 -SCR on Pt/HZSM-5 catalyst by tungsten doping. The results showed that tungsten was beneficial to the metal state of platinum in the catalyst and inhibited the formation of nitrate.…”

Section: H 2 -Scrmentioning

confidence: 99%

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

Liu

et al. 2019

Catalysts

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Nitrogen oxides (NO x ) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NO x , it is urgent to control NO x . According to the different mechanisms of NO x removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NO x . At the same time, the current research status and existing problems of different NO x removal technologies were revealed and the future development prospects were forecasted.Catalysts 2019, 9, 771 2 of 39 adsorption, oxidation, reduction, and plasma methods. In view of these attentive findings, adsorption method uses recyclable solid adsorbent material to adsorb NO x from flue gas through microporous structure, remarkably, environmentally friendly, no secondary pollution, and energy-saving and -efficient features make it stand out [18][19][20]. The oxidation process is a method that oxidizes NO into NO 2 or N 2 O 3 with high solubility under the action of an oxidant that is then absorbed by water or alkali solution. The process is simple and cost-saving, and is widely used in the wet flue gas denitrification process with relatively low cost and high removal efficiency of NO x ; except that the oxidized NO and SO 2 can be removed simultaneously to produce high value-added products [21][22][23]. The reduction method has the characteristics of high efficiency, cleanliness, and mildness; NO x removal can be realized at low temperature at present [24][25][26]. The plasma method is used to modify the surface of the catalyst, the dispersion of active species can be improved by plasma treatment, and the stability and low temperature activity of catalyst can be improved [27,28].Seldom, if ever, does a comprehensive article to introduce the current situation and treatment methods of removing NO x . In this paper, we tried to renovate, classify, and summarize the significant perspectives and most relevant findings reported in recent research articles and earlier reviews generalizing the mechanism analysis and research progress of NO x removal by adsorption, oxidation, reduction, and plasma methods, which can provide means for promoting the technological progress of pollution prevention, maintaining healthy development of factories continuously, studying the methods of removing NO x deeply, and mastering different technologies of removing NO x , as well as providing guidance for controlling the emission of NO x from motor vehicles such as diesel, gasoline, and so on. In order to improve the environmental quality and save the ecological environment, this paper further provides a convenient, low-cost, efficient, and economic guidance line.

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Promotion effect of tungsten on the activity of Pt/HZSM-5 for H2-SCR

Cited by 45 publications

References 42 publications

Tungsten-Based Catalysts for Environmental Applications

Tungsten-Based Catalysts for Environmental Applications

State-of-Art Review of NO Reduction Technologies by CO, CH4 and H2

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

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