In Situ DRIFTs Investigation of the Low-Temperature Reaction Mechanism over Mn-Doped Co3O4 for the Selective Catalytic Reduction of NOx with NH3

Hu, Hang; Cai, Shu; Li, Hongrui; Huang, Lei; Shi, Liyi; Zhang, Dengsong

doi:10.1021/acs.jpcc.5b06057

Cited by 230 publications

(122 citation statements)

References 61 publications

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“…[35,[49][50][51] As a consequence, active gaseous NO 2 species and nonactive bidentate nitrate desorption behavior were further investigated with the normalized method.…”

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confidence: 99%

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Liang

Liu

et al. 2016

ChemCatChem

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Antimony‐doped CeO2–WO3/TiO2 catalysts were prepared by a conventional ultrasonic‐assisted impregnation method and employed for selective catalytic reduction of NOx with NH3 at low temperature. Both experimental work and theoretical studies were employed to elucidate the effect of the antimony on promoting the CeO2–WO3/TiO2 catalyst. The catalytic activity of CeO2–WO3/TiO2 was largely improved after the addition of antimony oxide. It was found that antimony doping reduced the crystal size and strengthened the synergistic effect between the metal cations, which resulted in a favorable catalyst surface status with abundant active surface oxygen, Brønsted acid sites, and effective electron transfer. Both in situ diffuse reflectance infrared Fourier transform analysis and DFT calculation results revealed that the ammonia and NOx desorption behavior over the catalyst surface were considerably different. For the ammonia species, rather large amounts of the active NH4+ and NH3 species anchored on the surface of the Sb‐doped CeO2–WO3/TiO2. In view of the NOx species, the amount of nonactive bidentate nitrate species was largely reduced and the amount of active gaseous NO2 species was clearly enhanced, which lowered the activation energy of the catalytic process and gave rise to the elevated low‐temperature NH3 selective catalytic reduction activity. All these preferable properties resulted in the elevated de‐NOx activity of the Sb‐doped CeO2–WO3/TiO2 catalyst.

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“…[35,[49][50][51] As a consequence, active gaseous NO 2 species and nonactive bidentate nitrate desorption behavior were further investigated with the normalized method.…”

mentioning

confidence: 99%

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Liang

Liu

et al. 2016

ChemCatChem

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“…As demonstrated in Fig. 8, the band at 1,629 cm −1 , assigned to nitrite, and the bands at 1,578 and 1,294 cm −1 , assigned to bidentate and monodentate nitrate, respectively [19,20] disappeared at elevated temperature. Also, the broad bands from 3,000 to 3,600 cm −1 were gradually gone, indicating the disappearance of hydrogen bonding between water molecules and ceria surface [21].…”

Section: -2 In Situ Drift Studymentioning

confidence: 90%

CeO2-TiO2 catalyst prepared by physical mixing for NH3 selective catalytic reduction: Evidence about the migration of sulfates from TiO2 to CeO2 via simple calcination

Song

Youn

Lee

et al. 2016

Korean J. Chem. Eng.

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A mechanical mixture of CeO 2 and TiO 2 powder with a small amount of sulfate was applied for the selective catalytic reduction (SCR) of NO with NH 3 . After calcination at 500 o C, the mixed sample showed significantly enhanced activity and selectivity compared to the uncalcined one and, moreover, demonstrated even higher activity than the conventional V 2 O 5 /TiO 2 catalyst above 300 o C. Combined characterization results revealed that the main active sites were newly formed sulfate species on CeO 2 , the number of which increased with calcination. Temperatureresolved DRIFT spectra provided convincing evidence about the migration of sulfate species from TiO 2 to CeO 2 , as confirmed from the shift of ν(S=O) band as a result of the mechanical mixing and the subsequent calcination.

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“…[34] It can be seen that the intensity of this band for the MnTic atalyst is relatively loww hereas it is rather high for the CoTic atalyst. [48,53] It is worth noting that as trong band at 1208 cm À1 ,a ssigned to bridged nitrite, appeared after 3min, but gradually vanished with increasing adsorption time. It is reported that the oxidation property of the catalysti sad oubleedged characteristic for the SCR reaction.…”

Section: No + + O 2 Co-adsorptionmentioning

confidence: 98%

“…[48,53] It is worth noting that as trong band at 1208 cm À1 ,a ssigned to bridged nitrite, appeared after 3min, but gradually vanished with increasing adsorption time. [27,48,53,54] It can be seen that these bands were similart ot hose that appearedf or MnTi, and the stronger band intensity can be attributed to the introduction of CoO y . For the CoTic atalyst, the other bands can be attributed to the bidentate nitrate (1539 cm À1 ,1 292 cm À1 )a nd linear nitrite (1483 cm À1 ).…”

Section: No + + O 2 Co-adsorptionmentioning

confidence: 98%

Mn−Co Mixed Oxide Nanosheets Vertically Anchored on H₂Ti₃O₇ Nanowires: Full Exposure of Active Components Results in Significantly Enhanced Catalytic Performance

et al. 2018

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The full exposure of active ingredients plays an important role in the enhancement of catalytic performance. In this work, a series of novel catalysts, Mn−Co mixed oxide nanosheets with ultrathin thickness (about 3.5 nm) and different Mn/Co ratios (0.52, 0.69, and 1.52) vertically anchored on a support (H2Ti3O7 nanowires), are rationally developed. This unique structure not only fully exposes the active ingredients of the Mn−Co mixed oxides, but also is very favorable for the diffusion and transfer of gas molecules through the space between these standing nanosheets. As expected, the developed catalysts (MnOx‐CoOy/H2Ti3O7, MnCoTi), especially MnCoTi‐2 with the Mn/Co molar ratio of 0.69, present excellent low‐temperature selective catalytic reduction (SCR) performance, high N2 selectivity, superior water tolerance and stability. The relative turnover frequency (TOF) value over MnCoTi‐2 at 100 °C is as high as 9.25×10−4 s−1 under the gas hourly space velocity (GHSV) of 200 000 h−1, which is rarely reported among Mn‐Ti, Mn−Co, and Mn−Co‐Ti mixed oxide catalysts. The results of in situ diffuse reflectance infrared Fourier transform spectroscopy suggest that the coordinated NH3, NH4+ ions, adsorbed NO2, and bidentate nitrate are the reactive species and the Eley–Rideal and Langmuir–Hinshelwood mechanisms can be simultaneously involved on the surface of the MnCoTi‐2 at a relatively low temperature (90 °C).

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In Situ DRIFTs Investigation of the Low-Temperature Reaction Mechanism over Mn-Doped Co₃O₄ for the Selective Catalytic Reduction of NO_x with NH₃

Cited by 230 publications

References 61 publications

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

CeO2-TiO2 catalyst prepared by physical mixing for NH3 selective catalytic reduction: Evidence about the migration of sulfates from TiO2 to CeO2 via simple calcination

Mn−Co Mixed Oxide Nanosheets Vertically Anchored on H₂Ti₃O₇ Nanowires: Full Exposure of Active Components Results in Significantly Enhanced Catalytic Performance

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In Situ DRIFTs Investigation of the Low-Temperature Reaction Mechanism over Mn-Doped Co3O4 for the Selective Catalytic Reduction of NOx with NH3

Cited by 230 publications

References 61 publications

Investigations on the Antimony Promotional Effect on CeO2–WO3/TiO2 for Selective Catalytic Reduction of NOx with NH3

Investigations on the Antimony Promotional Effect on CeO2–WO3/TiO2 for Selective Catalytic Reduction of NOx with NH3

CeO2-TiO2 catalyst prepared by physical mixing for NH3 selective catalytic reduction: Evidence about the migration of sulfates from TiO2 to CeO2 via simple calcination

Mn−Co Mixed Oxide Nanosheets Vertically Anchored on H2Ti3O7 Nanowires: Full Exposure of Active Components Results in Significantly Enhanced Catalytic Performance

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In Situ DRIFTs Investigation of the Low-Temperature Reaction Mechanism over Mn-Doped Co₃O₄ for the Selective Catalytic Reduction of NO_x with NH₃

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Mn−Co Mixed Oxide Nanosheets Vertically Anchored on H₂Ti₃O₇ Nanowires: Full Exposure of Active Components Results in Significantly Enhanced Catalytic Performance