Catalytic performance of supported Ir catalysts for NO reduction with C 3 H 6 and CO in slight lean conditions

Doi, Yasuyuki; Haneda, Masaaki

doi:10.1016/j.cattod.2017.07.023

Cited by 12 publications

(5 citation statements)

References 36 publications

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“…Over the past years, many efforts have been devoted to developing highly efficient catalytic systems, particularly the noble metal catalysts, i. e ., platinum (Pt), [13] palladium (Pd), [14] Iridium (Ir), [15,16] etc., because of their high catalytic activity, oxidation resistance, and high‐temperature stability. Among them, Ir‐based catalysts have been demonstrated to be the most efficient ones [17–19] .…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…This difference demonstrates that the oxidation resistance can be improved by Ru introduction. A previous study has shown that there is a relationship between the oxidation resistance and acid strength . The strong acid strength may benefit the stability of Ir 0 under an oxidizing atmosphere.…”

Section: Resultsmentioning

confidence: 95%

“…A previous study has shown that there is a relationship between the oxidation resistance and acid strength. 35 The strong acid strength may benefit the stability of Ir 0 under an oxidizing atmosphere. The acid sites of as-made catalysts were investigated by in situ DRIFTS experiments (Figure 3d).…”

Section: Environmental Science and Technologymentioning

confidence: 99%

Insight into the Mechanism of Selective Catalytic Reduction of NO by CO over a Bimetallic IrRu/ZSM-5 Catalyst in the Absence/Presence of O₂ by Isotopic C¹³O Tracing Methods

Bai

Gao²,

Sun

et al. 2023

Environ. Sci. Technol.

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The development of efficient catalysts for the selective catalytic reduction of NO by CO (CO-SCR) in the presence of O 2 is highly desirable for controlling the emission of toxic gases from tailpipes. Here, a bimetallic IrRu/ZSM-5 catalyst was prepared for the selective catalytic reduction of NO by CO in the presence of O 2 (5%) for the low-temperature treatment of exhaust gas. IrRu/ZSM-5 afforded 90% NO x conversion in the range of 225−250 °C and maintained 90% NO x conversion after 12 h of reaction. Ru addition inhibited agglomeration of the Ir particles during the reduction process and provided more active sites for NO adsorption. Isotopic C 13 O tracing and in situ diffuse reflectance infrared Fouriertransform spectroscopy experiments were used to elucidate the CO-SCR mechanism in the absence or presence of O 2 . NCO could easily form on the surface of catalysts in the absence of O 2 , whereas NCO formation has been inhibited owing to the quick consumption of CO in the presence of O 2 . Moreover, some byproducts such as N 2 O and NO 2 are generated in the presence of O 2 . Finally, a possible mechanism for CO-SCR under different conditions was proposed based on in situ experiments and physicochemical analyses.

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“…Ir 0 sites are vital for the CO-SCR reaction and can be deactivated by oxidization. 31,44 A report showed that the oxidization resistance of Ir 0 may be related to the acid strength of the catalysts. 44 The NH 3 -temperature-programmed desorption (NH 3 -TPD) experimental results revealed that the acid strength of the catalysts was improved by modulating the amount of Sn added (Figure 4c).…”

Section: Structural Characterization Ofmentioning

confidence: 99%

“…31,44 A report showed that the oxidization resistance of Ir 0 may be related to the acid strength of the catalysts. 44 The NH 3 -temperature-programmed desorption (NH 3 -TPD) experimental results revealed that the acid strength of the catalysts was improved by modulating the amount of Sn added (Figure 4c). The desorption peak area of IrSn3.5@MFI was obviously larger than those of the other catalysts, suggesting that the number of acidic sites was greater than those of the other catalysts.…”

Section: Structural Characterization Ofmentioning

confidence: 99%

IrSn Bimetallic Clusters Confined in MFI Zeolites for CO Selective Catalytic Reduction of NO_x in the Presence of Excess O₂

Bai,

Miao,

Wang

et al. 2024

Environ. Sci. Technol.

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Catalytic performance of supported Ir catalysts for NO reduction with C 3 H 6 and CO in slight lean conditions

Cited by 12 publications

References 36 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

Insight into the Mechanism of Selective Catalytic Reduction of NO by CO over a Bimetallic IrRu/ZSM-5 Catalyst in the Absence/Presence of O₂ by Isotopic C¹³O Tracing Methods

IrSn Bimetallic Clusters Confined in MFI Zeolites for CO Selective Catalytic Reduction of NO_x in the Presence of Excess O₂

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Catalytic performance of supported Ir catalysts for NO reduction with C 3 H 6 and CO in slight lean conditions

Cited by 12 publications

References 36 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

Insight into the Mechanism of Selective Catalytic Reduction of NO by CO over a Bimetallic IrRu/ZSM-5 Catalyst in the Absence/Presence of O2 by Isotopic C13O Tracing Methods

IrSn Bimetallic Clusters Confined in MFI Zeolites for CO Selective Catalytic Reduction of NOx in the Presence of Excess O2

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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

Insight into the Mechanism of Selective Catalytic Reduction of NO by CO over a Bimetallic IrRu/ZSM-5 Catalyst in the Absence/Presence of O₂ by Isotopic C¹³O Tracing Methods

IrSn Bimetallic Clusters Confined in MFI Zeolites for CO Selective Catalytic Reduction of NO_x in the Presence of Excess O₂