In-situ DRIFT assessment on strengthening effect of cerium over FeO /TiO2 catalyst for selective catalytic reduction of NO  with NH3

Chitsazi, Hossein; Zhang, Ningqiang; Li, Lingcong; Liu, Xiaojun; Wu, Rui; He, Junda; Song, Liyun; He, Hong

doi:10.1016/j.jre.2020.05.004

Cited by 22 publications

(8 citation statements)

References 31 publications

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“…The absorption bands at 1410 cm –1 of the two catalysts could be assigned to the NH 3 adsorption on Brønsted acid sites (NH 4 + -B), which was also stronger on the CuO x /Al 2 O 3 -H catalyst. − Interestingly, there was no such band on Al 2 O 3 . Hence, combined with the deconvolved NH 3 adsorption spectra in Figure C, it could be concluded that this unique band at 1410 cm –1 might be ascribed to the NH 3 adsorption on Cu-OH sites . Thanks to the NH 3 activation capacity of CuO x -OH sites, more −NH 2 species located at 1555 and 1335 cm –1 could be observed on the CuO x /Al 2 O 3 -H catalyst (Figure S22).…”

Section: Resultsmentioning

confidence: 89%

“…Hence, combined with the deconvolved NH 3 adsorption spectra in Figure 3C, it could be concluded that this unique band at 1410 cm −1 might be ascribed to the NH 3 adsorption on Cu-OH sites. 47 Thanks to the NH 3 activation capacity of CuO x -OH sites, more −NH 2 species located at 1555 and 1335 cm −1 could be observed on the CuO x /Al 2 O 3 -H catalyst (Figure S22). 48,49 Pyridine-IR was also conducted to confirm the distribution of acid sites on the two catalysts (Figure S23).…”

Section: Introductionmentioning

confidence: 99%

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Unraveling the Promotion Effects of Dynamically Constructed CuO_x-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

et al. 2022

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The selective catalytic oxidation of ammonia (NH3-SCO) into N2 and H2O is a recognized effective protocol to eliminate excessive NH3 emission. Nevertheless, it is a great challenge for NH3-SCO catalysts to balance the NH3 oxidation activity with N2 selectivity. Herein, promotion effects of the dynamically constructed CuO x -OH interfacial sites for NH3 oxidation activity without the scarification of N2 selectivity were unraveled. The enrichment of coordination unsaturated Cu sites and Cu-OH acid sites in CuO x -OH interfacial sites optimized the adsorption and activation for NH3 and O2, leading to the over 9-fold increase in NH3 oxidation rate and the 40 kJ/mol decrease in apparent activation energy compared with the conventional CuO sites. Unexpectedly, the fast internal-selective catalytic reduction (i-SCR) mechanism was identified on CuO x -OH interfacial sites, which is characterized by the presence of consumable NO2 adsorbed species. This work paves an innovative way for the development of effective NH3-SCO catalysts and contributes to the deeper understanding of the reaction mechanism.

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Section: Resultsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Unraveling the Promotion Effects of Dynamically Constructed CuO_x-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

et al. 2022

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“…Operando DRIFTS monitored by MS was used to explore the reaction mechanisms of different catalysts. As shown in Figure 4a and 4d, the elimination of NH 3 -L (∼1627, 1252 cm −1 ), NH 4 + -B (1408 cm −1 ), 56 and -NH 2 species (1582 and 1338 cm −1 ) 57 50,59 and MS signals of N 2 O and NO x byproducts were noticed over all three catalysts, which resulted from the insufficient NH 3 adsorption at a high temperature. Nevertheless, the generation these byproducts over Pt/Al 2 O 3 was more pronounced, which may be due to the imide mechanism as previously reported (Figure S55).…”

Section: Resultsmentioning

confidence: 94%

“…Operando DRIFTS monitored by MS was used to explore the reaction mechanisms of different catalysts. As shown in Figure a and d, the elimination of NH 3 -L (∼1627, 1252 cm –1 ), NH 4 + -B (1408 cm –1 ), and -NH 2 species (1582 and 1338 cm –1 ) were found during NH 3 oxidation from 50 to 300 °C. The absence of nitrate and nitrite species indicated that Pt 1 CuO/Al 2 O 3 and CuO/Al 2 O 3 were not guided by the conventional internal SCR (i-SCR) mechanism.…”

Section: Resultsmentioning

confidence: 99%

Isolated Pt Atoms Embedded in CuO Nanocatalysts for Selective Oxidation of Ammonia

Lan,

Gao,

Hasegawa

et al. 2023

ACS Catal.

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Establishing a binary synergy is promising to break the scaling relationship in heterogeneous catalysis. In this study, we created CuO nanocatalysts with isolated Pt atoms to selectively oxidize NH3 to N2, which helps to reduce fine particulate matter air pollution. These nanocatalysts had a reaction rate 30 times higher than CuO catalysts at 160 °C and 30% higher N2 selectivity than Pt catalysts at 99% NH3 conversion. Our experimental and theoretical findings showed that a reaction field separation strategy was responsible for the improved performance. Specifically, isolated Pt atoms facilitated the adsorption/activation of O2 while adjacent Cu atoms facilitated NH3 adsorption/activation. Through operando infrared spectroscopy and theoretical calculations, we found that the weaker adsorption of the NO2 intermediate on Cu sites was crucial for better performance. This research sets the foundation for developing high-performance heterogeneous catalysts.

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“…At the same time, the peaks belonging to B acid sites (1475, 1691, 1643, 1575, 1459, and 1430 cm −1 ) and L acid sites (1287−1097 cm −1 ) appeared, and there was also obvious weakly adsorbed NH 3 at 927 cm −1 , both of them indicating that it had a strong adsorption of NH 3 . 64,65 After adsorption of NO, the peaks of monodentate nitrate (1541−1521 cm −1 ), free nitrate (1359 cm −1 ), bridged nitrate (1288 cm −1 ), and bidentate nitrate (1037 cm −1 ) appeared, 66 implying the catalyst can adsorb NO.…”

Section: In Situ Drift Analysis For De-nomentioning

confidence: 99%

Rational Regulation of Reducibility and Acid Site on Mn–Fe–BTC to Achieve High Low-Temperature Catalytic Denitration Performance

Song

Guo

et al. 2023

ACS Appl. Mater. Interfaces

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Selective catalytic reduction with ammonia is the mainstream technology of flue gas denitration (de-NO x ). The reducibility and acid site are two important factors affecting the de-NO x performance, and effective regulation between them is the key to obtain a highly efficient de-NO x catalyst. Herein, a series of Mn−Fe−BTC with different ratios of Mn and Fe are synthesized, among which 2Mn-1Fe-BTC with 2:1 molar ratio of Mn and Fe has excellent low-temperature (LT) de-NO x performance (above 90% NO conversion between 60 and 270 °C) and good tolerance to H 2 O and SO 2 poisoning (88% NO conversion at 150 °C with 100 ppm of SO 2 and/or 6% H 2 O). It is revealed that the reducibility properties and acid sites of Mn−Fe− BTC can be flexibly tuned by the ratio of Mn and Fe. The difference in electronegativity between Fe and Mn leads to the redistribution of valence electrons, which enables the controllable reducibility of Mn−Fe−BTC. Furthermore, different amounts of Mn and Fe lead to different electron transport, which determines the type and number of acid sites. The synergistic effect of Mn and Fe endows Mn−Fe−BTC with enhanced surface molecular adsorption capacity and enables the catalyst to selectively chemisorb NH 3 and NO at different active sites. This research provides guidance for the flexible regulation of reducibility and acid site of LT de-NO x catalyst.

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In-situ DRIFT assessment on strengthening effect of cerium over FeO /TiO2 catalyst for selective catalytic reduction of NO with NH3

Cited by 22 publications

References 31 publications

Unraveling the Promotion Effects of Dynamically Constructed CuO_x-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

Unraveling the Promotion Effects of Dynamically Constructed CuO_x-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

Isolated Pt Atoms Embedded in CuO Nanocatalysts for Selective Oxidation of Ammonia

Rational Regulation of Reducibility and Acid Site on Mn–Fe–BTC to Achieve High Low-Temperature Catalytic Denitration Performance

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In-situ DRIFT assessment on strengthening effect of cerium over FeO /TiO2 catalyst for selective catalytic reduction of NO with NH3

Cited by 22 publications

References 31 publications

Unraveling the Promotion Effects of Dynamically Constructed CuOx-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

Unraveling the Promotion Effects of Dynamically Constructed CuOx-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

Isolated Pt Atoms Embedded in CuO Nanocatalysts for Selective Oxidation of Ammonia

Rational Regulation of Reducibility and Acid Site on Mn–Fe–BTC to Achieve High Low-Temperature Catalytic Denitration Performance

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Unraveling the Promotion Effects of Dynamically Constructed CuO_x-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia

Unraveling the Promotion Effects of Dynamically Constructed CuO_x-OH Interfacial Sites in the Selective Catalytic Oxidation of Ammonia