Insights into deNOx processing over Ce-modified Cu-BTC catalysts for the CO-SCR reaction at low temperature by in situ DRIFTS

Zhang, Yu; Zhao, Ling; Duan, Jun; Bi, Shuping

doi:10.1016/j.seppur.2019.116081

Cited by 84 publications

(31 citation statements)

References 43 publications

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“…The band at 2107 cm −1 is due to CO species adsorbed on iridium (Ir 0 −CO), while that at 2173 cm −1 can be assigned to CO linearly bonded to Ir δ+ sites [44,45] . Interestingly, when NO, CO and O 2 were simultaneously adsorbed (Figure 12 a–c), the measured in situ DRIFT spectra showed that except for Ir 1 /m‐WO 3, the bands assigning to NO 3 − disappeared in the cases of Ir NPs/m‐WO 3 and Ir/non‐m‐WO 3 , but there was the appearance of a new intensive band at 1743 cm −1 corresponding to N 2 O 4 , [46,47] suggesting that in both cases NO could be easily oxidized. Thus, it is clear that for Ir 1 /m‐WO 3 , the intermediate of the adsorbed NO is NO 3 − and that of the adsorbed CO is Ir 0 −CO and CO−Ir δ+ .…”

Section: Resultsmentioning

confidence: 98%

Single Ir Atoms Anchored on Ordered Mesoporous WO₃ Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Jiang

Liu

et al. 2021

ChemCatChem

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Under oxygen‐rich conditions, achieving a selective and efficient reduction of NO by CO is always challenging. Here, we report the synthesis of the catalyst consisting of single Ir atoms anchored on mesoporous WO3 (denoted as Ir1/m‐WO3) using a facile template method followed by wet impregnation. X‐ray diffraction and transmission electron microscope studies indicated that the Ir atoms were distributed uniformly on the internal surface of m‐WO3. When tested for the reduction of NO by CO, the Ir1/m‐WO3 catalyst with a low Ir loading of 0.28 wt % exhibited excellent catalytic performance in the presence of 2 vol % O2 (volume ratio of CO to O2 being 1 : 10), achieving a NO conversion of 73 % and N2 selectivity of 100 % at 350 °C. In particular, its turnover frequency (TOF) value reached 0.30 s−1 at 200 °C, which is six times higher than that of the catalyst with Ir nanoparticles supported on mesoporous WO3 (0.05 s−1). The superior catalytic performance of Ir1/m‐WO3 is attributed to the formation of the isolated Ir atoms and the more newly generated Ir‐WO3 interfaces that can promote the adsorption and activation of NO, and the presence of accessible mesopores in m‐WO3 that facilitates the mass transfer of NO and CO. This study brings a new fundamental understanding of active sites in Ir‐based catalysts for the CO+NO reaction and provides a new way to the design and synthesis of single‐atom catalysts, especially precious metal catalysts for emissions control.

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Section: Resultsmentioning

confidence: 98%

Single Ir Atoms Anchored on Ordered Mesoporous WO₃ Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Jiang

Liu

et al. 2021

ChemCatChem

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“…In addition, the reaction peak appeared at 1481 cm À 1 and 1562 cm À 1 , which may be caused by bicarbonate and carboxylate. [47] Finally, the characteristic vibration peaks corresponding to gaseous CO and CO 2 appear at 2139 cm À 1 , 2179 cm À 1 and 2340 cm À 1 , 2360 cm À 1 , respectively. It is worth noting that the peak of Cu + -CO species also appears at 2108 cm À 1 .…”

Section: Study Of In Situ Driftsmentioning

confidence: 97%

“…At the same time, the NO peaks at 1849 and 1912 cm À 1 are gas phase NO peaks, 2175 cm À 1 and 2240 cm À 1 may belong to gas phase CO, and the peak intensity increases with the increase of temperature. [45][46][47] The overlapping peaks at 2335 cm À 1 and 2360 cm À 1 can be attributed to the co-occurrence of CO 2 and NO + . Especially after 200 °C, the intensity of the peaks increases significantly, which may be related to CO's late participation in the reaction to produce CO 2 .…”

Section: Study Of In Situ Driftsmentioning

confidence: 98%

“…[45,46] The monodentate nitrates have vibration peaks at 1408 cm À 1 and 1480 cm À 1 , and the former belongs to unstable linear monodentate nitrates. [47] In addition, there are two bands in 1849 cm À 1 and 1910 cm À 1 , which can be classified as gaseous NO, and at 2335-2360 cm À 1 , they can be classified as NO + species. As the temperature rises, the bidentate nitrates at 1555 cm À 1 bicuspid nitrate gradually decomposed into chelating bidentate nitrates at 1535 cm À 1 and 1575 cm À 1 , and the peak intensity increased with the increase of temperature.…”

Section: Study Of In Situ Driftsmentioning

confidence: 99%

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Activity Test and Mechanism Study of 3DOM Ce_0.8M_0.1Zr_0.1O₂ (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

Liu

Líu

et al. 2021

ChemCatChem

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The results show that the NO conversion rate of 3DOM Ce 0.8 Cu 0.1 Zr 0.1 O 2 catalyst at a lower temperature (150 °C) is close to 60 %. Besides, 3DOM Ce 0.8 Cu 0.1 Zr 0.1 O 2 kept a stable NO removal efficiency within a wide range of gas hourly space velocity (GHSV) and long reaction time and exhibited remarkable resistance to H 2 O and SO 2 poisoning, both individually and simultaneously. At the same time, the formation of the 3DOM structure not only improves the reduction performance and surface active sites of the catalyst, but also forms more oxygen defects and Ce 3 + in the catalyst due to the strong synergistic effect of metal ions and ceria, which improves the surface oxygen concentration of the composite oxide catalyst and further improves the catalytic activity. In addition, the doping of copper ions on the surface of the 3DOM Cu-CZ catalyst can improve the activity of the catalyst and it can get trapped by CO to form Cu + -CO, which plays an important role in the NO + CO reaction at low temperature. The existence of oxygen vacancy at high temperature is beneficial to the activation of O 2 and the dissociation of NO in the process of CO oxidation. The reaction of NO + CO over 3DOM Cu-CZ catalyst follows LÀ H and EÀ R mechanism respectively.

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“…Although plasma assisted techniques for the flue gas treatment have shown good progress, yet the industrial applicability of plasma-based techniques is questionable. 30 Another recent study conducted by Zhao et al, 31 showed deNOx effect using Ce-modified Cu-BTC catalysts in presence of CO at low temperature by in situ DRIFTS. The results demonstrated that the adsorption modes of NO on the catalysts form the following species; monodentate nitrites, chelating bidentate nitrates, bridging bidentate nitrates, trans-N 2 O 2 2and NOspecies (Scheme S1), whereas the adsorption forms of CO form hydrogen carbonate, carbonate and carbonyl species (Scheme S2).…”

Section: R a F Tmentioning

confidence: 98%

Mechanistic studies on the conversion of NO gas on urea-iron and copper metal organic frameworks at low temperature conditions: in situ infrared spectroscopy and Monte Carlo investigations

2021

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Nitrogen oxides (NOx) emissions from high temperature combustion processes under fuel-lean conditions continue to be a challenge for the energy industry. Selective catalytic reduction (SCR) has been possible with metal oxides and zeolites. There is still the need to identify catalytic materials that are efficient in reducing NOx to environmentally benign nitrogen gas at temperatures lower than 200°C. Metal-organic frameworks (MOFs) emerged as a class of highly porous materials with unique physical and chemical properties. This study is motivated by the lack of systematic investigations on SCR using MOFs under industrially-relevant conditions. Here, we investigate the extent of NO conversion with two commercially-available MOFs; Basolite F300 (Fe-BTC) and HKUST-1 (Cu-BTC), mixed with solid urea as a source for the reductant, ammonia gas. For comparison, experiments were also conducted using cobalt ferrite (CoFe2O4) as a non-porous counterpart to relate its reactivity to those obtained from MOFs. Fourier-transform infrared spectroscopy (FTIR) was utilized to identify gas and surface species the temperature range 115 -180°C. Computational analysis was performed using Monte Carlo (MC) simulations to quantify adsorption energies of different surface species. The results show that the rate of ammonia production from the in situ solid urea decomposition was higher using CoFe2O4 than Fe-BTC and Cu-BTC, and that there is very limited conversion of NO on the mixed solid urea-MOF systems due to site blocking. The main conclusions from this study is that MOFs have limited abilities in converting NO under low temperature conditions, and that surface regeneration requires additional experimental steps.

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Insights into deNOx processing over Ce-modified Cu-BTC catalysts for the CO-SCR reaction at low temperature by in situ DRIFTS

Cited by 84 publications

References 43 publications

Single Ir Atoms Anchored on Ordered Mesoporous WO₃ Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Single Ir Atoms Anchored on Ordered Mesoporous WO₃ Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Activity Test and Mechanism Study of 3DOM Ce_0.8M_0.1Zr_0.1O₂ (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

Mechanistic studies on the conversion of NO gas on urea-iron and copper metal organic frameworks at low temperature conditions: in situ infrared spectroscopy and Monte Carlo investigations

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Insights into deNOx processing over Ce-modified Cu-BTC catalysts for the CO-SCR reaction at low temperature by in situ DRIFTS

Cited by 84 publications

References 43 publications

Single Ir Atoms Anchored on Ordered Mesoporous WO3 Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Single Ir Atoms Anchored on Ordered Mesoporous WO3 Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Activity Test and Mechanism Study of 3DOM Ce0.8M0.1Zr0.1O2 (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

Mechanistic studies on the conversion of NO gas on urea-iron and copper metal organic frameworks at low temperature conditions: in situ infrared spectroscopy and Monte Carlo investigations

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Single Ir Atoms Anchored on Ordered Mesoporous WO₃ Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Single Ir Atoms Anchored on Ordered Mesoporous WO₃ Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen‐rich Conditions

Activity Test and Mechanism Study of 3DOM Ce_0.8M_0.1Zr_0.1O₂ (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**