Influence of attrition milling on V/Ti catalysts for the selective oxidation of ammonia

Kwon, Dong Wook; Lee, Sang Moon; Hong, Sung Chang

doi:10.1016/j.apcata.2015.02.007

Cited by 28 publications

(12 citation statements)

References 45 publications

(45 reference statements)

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“…The valence state of the metal on the surface of the catalyst is known to be an important factor in the SCR reaction activity (e.g., V 5+ ↔ V 3+ + V 4+ or Ce 3+ ↔ Ce 4+ ). , It can also be used as information for confirming the formation of various compounds on the catalyst. Therefore, the following XPS analysis was performed to investigate the effect of P on the SCR reaction activity and the formation of P compounds on the surface of the catalyst.…”

Section: Resultsmentioning

confidence: 99%

Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

Nam

Yeo

Hong

2019

Ind. Eng. Chem. Res.

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We investigated the effects of phosphorus (P) on the catalytic activity and properties of V/W/Ti and V/Sb/Ce/Ti. As a result of investigating changes in the physicochemical properties of each catalyst added with P, in the V/W/Ti catalyst, P was bound to vanadium or tungsten in the form of PO 3 − (metaphosphate) and produced phosphate species. During this process, the Brønsted acid site on the catalyst surface was greatly increased, and the adsorption amount of ammonia of the catalyst was increased. However, the active site (VO) and redox properties were reduced, which inhibited the reactivity of adsorbed ammonia, and as a result, the selective catalytic reduction (SCR) efficiency was decreased. In contrast, V/Sb/Ce/Ti catalysts preferentially produce Ce−phosphate and Sb−phosphate. In this process, the production of PO 3 − and the reduction of the active site were suppressed, indicating high P resistance. In addition, with a low P content, the redox properties were increased, such that the SCR activity was improved.

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Section: Resultsmentioning

confidence: 99%

Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

Nam

Yeo

Hong

2019

Ind. Eng. Chem. Res.

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“…In contrast, transition metal catalysts, such as CuO/Al 2 O 3 , 25 V 2 O 5 /TiO 2 , 26 Mn–TiO 2 , 27 Cu/SSZ-13, 28 and Fe/ZSM-5, 29 usually possess a mild redox property, which means they exhibit inferior low-temperature NH 3 conversion efficiency but high N 2 selectivity. Recently, the concept of bifunctional catalysts has been proposed to combine noble metals and transition metal oxides in order to obtain excellent low-temperature catalytic activity and N 2 selectivity simultaneously.…”

Section: Introductionmentioning

confidence: 99%

A mixed catalyst prepared by mechanically milling VW/TiO₂ and low content of Pt/Al₂O₃ for SCO of high-concentration NH₃

et al. 2022

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“…NH 3 adsorption on the acid sites of the catalyst is the first step of the NH 3 –SCR and NH 3 oxidation reactions, and the NH 3 adsorption amount and distribution are important to reaction activity . The results of the NH 3 -TPD analyses are shown in Figure and Table .…”

Section: Resultsmentioning

confidence: 99%

“…NH 3 adsorption on the acid sites of the catalyst is the first step of the NH 3 −SCR and NH 3 oxidation reactions, and the NH 3 adsorption amount and distribution are important to reaction activity. 39 The results of the NH 3 -TPD analyses are shown in Figure 7 and Table 2. According to the comparison of VWT and VT, the introduction of W increased the total acid amount from 303 to 365 μmol/m 2 .…”

Section: H 2 -Tpr Characterizationmentioning

confidence: 99%

Ca Doping Effect on the Competition of NH₃–SCR and NH₃ Oxidation Reactions over Vanadium-Based Catalysts

et al. 2021

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The Ca poisoning effect constrains vanadium-based catalysts from further application in high-calcium content flue gas, and the deactivation effect of CaO on V2O5–WO3/TiO2 (VWT) and V2O5/TiO2 (VT) catalysts has been investigated from a new perspective. As the NH3 selective catalytic reduction (NH3–SCR) results showed, the NO conversion at 400 °C declined by 71.7% for VT and by 34.8% for VWT after CaO doping, and the decrease in NO conversion for NH3–SCR at temperatures greater than 300 °C was mainly caused by the competition of the NH3 oxidation reaction. The characterization of catalysts by NH3–SCR, XRD, Raman spectroscopy, H2-TPR, NH3-TPD, and TEM showed that the number of surface acid sites decreased and that the oxidation and reduction properties of the catalysts all deteriorated after CaO doping, which is the primary reason for the decrease in NO conversion. CaO also affected NH3 oxidation, and the L-NH3 adsorbed on CaO favored the NH3 oxidation reaction, as DRIFTS showed. NH3 reaction pathways changed by CaO doping because NH3 oxidation becomes more competitive at temperatures greater than 300 °C. Density functional theory (DFT) calculations confirmed the NO formation pathway on CaO, and the competition mechanism of NH3–SCR and NH3 oxidation reactions has been described, which has hardly been reported.

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Influence of attrition milling on V/Ti catalysts for the selective oxidation of ammonia

Cited by 28 publications

References 45 publications

Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

A mixed catalyst prepared by mechanically milling VW/TiO₂ and low content of Pt/Al₂O₃ for SCO of high-concentration NH₃

Ca Doping Effect on the Competition of NH₃–SCR and NH₃ Oxidation Reactions over Vanadium-Based Catalysts

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Influence of attrition milling on V/Ti catalysts for the selective oxidation of ammonia

Cited by 28 publications

References 45 publications

Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

A mixed catalyst prepared by mechanically milling VW/TiO2 and low content of Pt/Al2O3 for SCO of high-concentration NH3

Ca Doping Effect on the Competition of NH3–SCR and NH3 Oxidation Reactions over Vanadium-Based Catalysts

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A mixed catalyst prepared by mechanically milling VW/TiO₂ and low content of Pt/Al₂O₃ for SCO of high-concentration NH₃

Ca Doping Effect on the Competition of NH₃–SCR and NH₃ Oxidation Reactions over Vanadium-Based Catalysts