Two steps synthesis of CeTiOx oxides nanotube catalyst: Enhanced activity, resistance of SO2 and H2O for low temperature NH3-SCR of NOx

Zhang, Zhiping; Li, Rumin; Wang, Mengjie; Li, Yushi; Tong, Yongming; Yang, Piaoping; Zhu, Yujun

doi:10.1016/j.apcatb.2020.119542

Cited by 221 publications

(102 citation statements)

References 73 publications

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“…These results suggested that the intrinsic properties governing the direct oxidation of NO were different from that of NH 3 oxidation. Combined with the results listed in Table 4, it can be deduced that surface oxygen plays a crucial role in NO oxidation to NO 2 over the Fe-M catalysts [6,57,58].…”

Section: Direct Oxidation Of Nh 3 and Nomentioning

confidence: 70%

“…For metal oxide NH 3 -SCR catalysts, generally, surface oxygen (O α ) is important for the oxidation of NO to NO 2 , thus promoting the "fast-SCR" reaction at low-temperature [6,57,58]. In addition, the over-oxidation of NH 3 accounted for the decreased NO x conversion at high temperatures [1,13,16,63,64].…”

Section: Discussionmentioning

confidence: 99%

“…A decrease in surface area induced by the assistance of CTAB in the preparation process was also observed for Fe-Ti and Fe-Mo, with detailed information shown in Table 2. 57 Fe Mössbauer spectroscopy measurements were carried out to confirm the crystalline phase of the iron oxides present, with results shown in Figure S2. The data were fitted using Moss Winn with parameters including isomer shift (mm s −1 ), quadrupole splitting (mm s −1 ), internal hyperfine field (T), and area listed in Table S1.…”

Section: Kinetic Studiesmentioning

confidence: 99%

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Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

et al. 2021

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Iron-based oxide catalysts for the NH3–SCR (selective catalytic reduction of NOx by NH3) reaction have gained attention due to their high catalytic activity and structural adjustability. In this work, iron–niobium, iron–titanate and iron–molybdenum composite oxides were synthesized by a co-precipitation method with or without the assistance of hexadecyl trimethyl ammonium bromide (CTAB). The catalysts synthesized with the assistance of CTAB (FeM0.3Ox-C, M = Nb, Ti, Mo) showed superior SCR performance in an operating temperature range from 150 °C to 400 °C compared to those without CTAB addition (FeM0.3Ox, M = Nb, Ti, Mo). To reveal such enhancement, the catalysts were characterized by N2-physisorption, XRD (Powder X-ray diffraction), NH3-TPD (temperature-programmed desorption of ammonia), DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy), XPS (X-ray Photoelectron Spectroscopy), and H2-TPR (H2-Total Physical Response). It was found that the crystalline phase of Fe2O3 formed was influenced by the presence of CTAB in the preparation process, which favored the formation of crystalline γ-Fe2O3. Owing to the changed structure, the redox-acid properties of FeM0.3Ox-C catalysts were modified, with higher exposure of acid sites and improved ability of NO oxidation to NO2 at low-temperature, both of which also contributed to the improvement of NOx conversion. In addition, the weakened redox ability of Fe prevented the over-oxidation of NH3, thus accounting for the greatly improved high-temperature activity as well as N2 selectivity.

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Section: Direct Oxidation Of Nh 3 and Nomentioning

confidence: 70%

Section: Discussionmentioning

confidence: 99%

Section: Kinetic Studiesmentioning

confidence: 99%

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Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

et al. 2021

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“…Hence, to improve the activity of the catalyst, the combination of Ce and Nb in a catalyst system is strongly recommended (Jawaher et al 2018). Typically, the catalyst was usually a precious metal or transition metal supported on TiO 2 or Al 2 O 3 , which exhibit good reducibility as well as large surface oxygen vacancies (Tian et al 2020, Zhang et al 2021).…”

Section: Introductonmentioning

confidence: 99%

Remarkable Enhancement In The N2- Selectivity of NH3-SCR Over The CeNb3Fe0.3/TiO2 Catalyst In The Presence of Chlorobenzene

Zang

Liu

et al. 2021

Preprint

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The simultaneous removal of NOx and dioxins is the frontier of environmental catalysis, which is still in the initial stage and poses several challenges. In this study, a series of CeNb3Fex/TiO2 (x = 0, 0.3, 0.6, and 1.0) catalysts were prepared by the sol-gel method and examined for the synergistic removal of NOx and chlorobenzene. The CeNb3Fe0.3/TiO2 catalyst exhibits an optimum catalytic performance, with an NOx conversion greater than 95 % at 260-380 °C. It also exhibited an optimal CB oxidation activity, in which CB promoted both the NOx conversion and N2 selectivity below 250 °C. Moreover, the more favourable ratios of Ce4+ to Ce3+, and plentiful surface adsorbed oxygen species are the reasons why CeNb3Fe0.3/TiO2 catalyst has better catalytic activity than other catalysts at lower temperature. Simultaneously, owing to the modulation of Fe to the redox properties of Ce and Nb, the large number of oxygen vacancies and acid sites, the CeNb3Fe0.3/TiO2 catalyst is is beneficial to NOx reduction and CB oxidation. Further, the results of in situ DRIFTS study reveal the NH3-SCR reactions over CeNb3Fex/TiO2 catalysts are mainly controlled by the L-H mechanism (< 200 °C) and E-R mechanism (> 200 °C), respectively.

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“…Furthermore, controlling NO and Hg 0 emissions by utilizing SCR and ACI independently confronts several inevitable shortcomings such as large equipment investment, high land requirement, huge maintaining and operating costs (Gao et al, 2018a;Gao et al, 2018b;Chen et al, 2020). It is essential to use the ameliorative SCR catalyst to achieve efficient reduction of NOx and oxidation of Hg 0 without subjoining equipment for considering comprehensive benefits, various types of SCR catalysts have been studied to that Zhang et al, 2021). Fortunately, it is well accepted that vanadium-based SCR catalyst can make part Hg 0 oxidize to Hg 2+ , but the converting ability from Hg 0 to Hg 2+ is relatively limited in low chlorine flue gas (Jiang et al, 2018;Zhang et al, 2018;Chen et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

LaOx modified MnOx loaded biomass activated carbon and its enhanced performance for simultaneous abatement of NO and Hg0

Xie

et al. 2021

Environ Sci Pollut Res

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A battery of agricultural straw derived biomass activated carbons supported LaOx modified MnOx (LaMn/BACs) was prepared by a facile impregnation method and then tested for the efficiency of simultaneous abatement of NO and Hg 0 . 15%LaMn/BAC manifested excellent removal efficiency of Hg 0 (100%) and NO (86.7%) at 180 °C, which also exhibited splendid resistance to SO2 and H2O. The interaction between Hg 0 removal and NO removal was explored, thereinto Hg 0 removal had no influence on NO removal, while NO removal preponderated over Hg 0 removal. The inhibitory effect of NH3 was greater than the accelerative effect of NO and O2 on Hg 0 removal. The physicochemical characterization of related samples were characterized by SEM, XRD, BET, H2-TPR, NH3-TPD and XPS. After incorporating suitable LaOx into 15%Mn/BAC, the synergistic effect between LaOx and MnOx contributed to the improvement of BET surface area and total pore volume, the promotion of redox ability, surface active oxygen species and acid sites, inhibiting the crystallization of MnOx. 15%LaMn/BAC has the best catalytic oxidation activity at low temperature. That might be answerable for superior performance and preferable tolerance to SO2 and H2O. Finally, the principle of catalytic oxidation was also discussesed in this article.

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Two steps synthesis of CeTiOx oxides nanotube catalyst: Enhanced activity, resistance of SO2 and H2O for low temperature NH3-SCR of NOx

Cited by 221 publications

References 73 publications

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

Remarkable Enhancement In The N2- Selectivity of NH3-SCR Over The CeNb3Fe0.3/TiO2 Catalyst In The Presence of Chlorobenzene

LaOx modified MnOx loaded biomass activated carbon and its enhanced performance for simultaneous abatement of NO and Hg0

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