Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH<sub>3</sub>-SCR reaction

Woo, Jung Won; Leistner, Kirsten; Bernin, Diana; Ahari, Homayoun; Shost, Mark; Zammit, Michael; Olsson, Louise

doi:10.1039/c8cy00147b

Cited by 45 publications

(22 citation statements)

References 67 publications

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“…All the different stretching vibrations are referenced in Table for more convenience. Moreover, the vibrations at 891 and 844 cm −1 assigned to copper cations interfering with T−O−T structure (as Si−O−Si or Si−Al−Si) for type 1 in the former and type 2 perturbation in the latter were exclusively observed for Cu‐SAPO‐34‐IE catalyst Figure b. As expected, H‐SAPO‐34 support Figure a.…”

Section: Resultssupporting

confidence: 62%

“…The intensity of these two 2150 cm −1 and 2175 cm −1 bands decreased during the desorption process, which suggest the gradual decrease of CO coverage and the removal of gaseous CO. Next, two new bands at 2136 and 2154 cm −1 appeared at 200 °C, which are associated to the formation of the above mentioned carbonyl complex, and more specifically, to the Cu + −CO species coordinate to the O atoms on two different sites of the zeolite framework. These two bands are associated to the Cu + species near of 6MR positions and Cu + cations near of 8MR, respectively . Indeed, a chemical vibration shift between 35 °C and 200 °C was firstly observed, indicating the conversion of Cu + −(CO) 2 to Cu + −CO species, which is associated to the Cu + adsorbates interaction modification within the catalyst cavities.…”

Section: Resultsmentioning

confidence: 90%

“…Indeed, a chemical vibration shift between 35 °C and 200 °C was firstly observed, indicating the conversion of Cu + −(CO) 2 to Cu + −CO species, which is associated to the Cu + adsorbates interaction modification within the catalyst cavities. Moreover, during the desorption process, the band at 2154 cm −1 decreased while the band at 2136 cm −1 increased in temperature, which could indicates the migration of some copper species in a more confined position, such as isolated Cu + into 6MR positions …”

Section: Resultsmentioning

confidence: 99%

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Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances

et al. 2020

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In the present study, the catalytic role and behavior of different copper cluster configurations during NH 3 SCR, NO and NH 3 oxidation reactions will be studied in detail. For this purpose, two preparation methods were performed. The physico-chemical and surface properties were characterized by different techniques, such as XRD, ICP, N 2 ads/des, HR-TEM, XPS, NMR, ex-situ/in-situ DRIFT, NH 3 TPD and H 2 TPR, in order to evaluate the impact of copper incorporation method on redox active sites, and, as a consequence, to better understand the mechanism of the NH 3 SCR reaction. catalysts were then exposed to He for 30 min to remove all the physically adsorbed species before starting the desorption temperature program, which consisted of a ramp of 2°C · min À 1 until 500°C. Desorbed ammonia was analyzed by Fourier Transform Infrared (FTIR) spectrometer (NICOLET) equipped with a heated 2 m gas cell and a DTGS detector. 4 5 6 7 8

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Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

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Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances

et al. 2020

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“…Due to the different paths, the amount of Si in the framework will most likely not correlate directly to the amount of ion exchange sites. Whether the Si mostly follows the SM2, SM3, or a combination of these depends on the synthesis procedure [31]. Pappas et al reported a thorough investigation of Cu-exchanged SSZ-13 for the DMTM reaction [14].…”

Section: Introductionmentioning

confidence: 99%

Comparing the Nature of Active Sites in Cu-loaded SAPO-34 and SSZ-13 for the Direct Conversion of Methane to Methanol

et al. 2020

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On our route towards a more sustainable future, the use of stranded and underutilized natural gas to produce chemicals would be a great aid in mitigating climate change, due to the reduced CO2 emissions in comparison to using petroleum. In this study, we investigate the performance of Cu-exchanged SSZ-13 and SAPO-34 microporous materials in the stepwise, direct conversion of methane to methanol. With the use of X-ray absorption spectroscopy, infrared (in combination with CO adsorption) and Raman spectroscopy, we compared the structure–activity relationships for the two materials. We found that SSZ-13 performed significantly better than SAPO-34 at the standard conditions. From CH4-TPR, it is evident that SAPO-34 requires a higher temperature for CH4 oxidation, and by changing the CH4 loading temperature from 200 to 300 °C, the yield (μmol/g) of SAPO-34 was increased tenfold. As observed from spectroscopy, both three- and four-fold coordinated Cu-species were formed after O2-activation; among them, the active species for methane activation. The Cu speciation in SAPO-34 is distinct from that in SSZ-13. These deviations can be attributed to several factors, including the different framework polarities, and the amount and distribution of ion exchange sites.

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“…For low temperature NH 3 -SCR denitrification catalyst, it is very crucial to study denitrification mechanism for further improving its activity [162,163]. Ryu et al [164] studied the location of active sites in NH 3 -SCR reaction, mainly at Lewis acid sites on the catalyst surface.…”

Section: Nh 3 -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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Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH₃-SCR reaction

Abstract: Cu/SAPO-34(TEA) only exhibited minor deactivation and mostly recovered its original activities, while Cu/SAPO-34(MO) showed major deactivation and was not fully regenerated during low temperature NH3-SCR reaction.

Cited by 45 publications

References 67 publications

Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances

Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances

Comparing the Nature of Active Sites in Cu-loaded SAPO-34 and SSZ-13 for the Direct Conversion of Methane to Methanol

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

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Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH3-SCR reaction

Abstract: Cu/SAPO-34(TEA) only exhibited minor deactivation and mostly recovered its original activities, while Cu/SAPO-34(MO) showed major deactivation and was not fully regenerated during low temperature NH3-SCR reaction.

Cited by 45 publications

References 67 publications

Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH3‐SCR Performances

Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH3‐SCR Performances

Comparing the Nature of Active Sites in Cu-loaded SAPO-34 and SSZ-13 for the Direct Conversion of Methane to Methanol

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

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Product

Resources

About

Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH₃-SCR reaction

Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances

Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances