Applicability of V2O5-WO3/TiO2 Catalysts for the SCR Denitrification of Alumina Calcining Flue Gas

Ning, Ruliang; Chen, Li; Li, Erwei; Liu, Xiaolong; Zhu, Tong

doi:10.3390/catal9030220

Cited by 16 publications

(9 citation statements)

References 52 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To examine this, NH 3 -TPD experiments were conducted. It can be seen from Figure 6B that the samples have three NH 3 desorption peaks from 50~500 • C. For sample A, two desorption peaks can be observed at 135 • C and 192 • C, which can be attributed to NH 4+ bound to weak Brønsted acid sites [38]. Whereas, the third peak is centered at 267 • C (strong peak), respectively.…”

Section: Characterizationmentioning

confidence: 94%

Low-Temperature Selective Catalytic Reduction of NO with NH3 over Natural Iron Ore Catalyst

2019

View full text Add to dashboard Cite

The selective catalytic reduction of NO with NH3 at low temperatures has been investigated with natural iron ore catalysts. Four iron ore raw materials from different locations were taken and processed to be used as catalysts. The methods of X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the materials. The results showed that the sample A (comprised mainly of α-Fe2O3 and γ-Fe2O3), calcined at 250 °C, achieved excellent selective catalytic reduction (SCR) activity (above 80% at 170–350 °C) and N2 selectivity (above 90% up to 250 °C) at low temperatures. Suitable calcination temperature, large surface area, high concentration of surface-adsorbed oxygen, good reducibility, lots of acid sites and adsorption of the reactants were responsible for the excellent SCR performance of the iron ore. However, the addition of H2O and SO2 in the feed gas showed some adverse effects on the SCR activity. The FT-IR analysis indicated the formation of sulfate salts on the surface of the catalyst during the SCR reaction in the presence of SO2, which could cause pore plugging and result in the suppression of the catalytic activity.

show abstract

Section: Characterizationmentioning

confidence: 94%

Low-Temperature Selective Catalytic Reduction of NO with NH3 over Natural Iron Ore Catalyst

2019

View full text Add to dashboard Cite

show abstract

“…Figure 4B shows the deconvolution of the O 1s spectrum. The binding energy at 529.9-530.0 eV corresponds to the lattice oxygen O 2− (denoted by Oβ), whereas, the sub-bands at higher binding energy (531.1-531.4) were assigned to surface adsorbed oxygen such as Oor O2 2-which correspond to defect oxide/hydroxyl-like group (denoted as Oα) [31]. Surface chemisorbed oxygen (Oα) is very active in oxidation reactions because its mobility is higher than the lattice oxygen (Oβ) [32], and the high SCR activity could be correlated with the high content of chemisorbed oxygen on the catalyst's surface.…”

Section: Characterizationmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

Comparision on the Low-Temperature NH3-SCR Performance of γ-Fe2O3 Catalysts Prepared by Two Different Methods

et al. 2019

View full text Add to dashboard Cite

Maghemite (γ-Fe2O3) catalysts were prepared by two different methods, and their activities and selectivities for selective catalytic reduction of NO with NH3 were investigated. The methods of X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) were used to characterize the catalysts. The resulted demonstrated that the γ-Fe2O3 nanoparticles prepared by the facile method (γ-Fe2O3–FM) not only exhibited better NH3-SCR activity and selectivity than the catalyst prepared by the coprecipitation method but also showed improved SO2 tolerance. This superior NH3-SCR performance was credited to the existence of the larger surface area, better pore structure, a high concentration of lattice oxygen and surface-adsorbed oxygen, good reducibility, a lot of acid sites, lower activation energy, adsorption of the reactants, and the existence of unstable nitrates on the surface of the γ-Fe2O3–FM.

show abstract

“…The amount of NH3 produced in each peak should be related to the amounts of the different acid sites. However an accurate quantification is rarely allowed because the TPD peaks generally overlap as for the NH3-TPD on V2O5-WO3-TiO2 catalysts [20][21][22][23][24][25][26][27][28]. This is due to (a) the presence of NH3ads-L and NH4 + species having activation energies of desorption depending on the coverages : Ed() and (b) the contribution of NH3 readsorption during the TPD which is rarely prevented on conventional catalysts as shown by Demmin and Gorte [29].…”

Section: Introductionmentioning

confidence: 99%

Individual amounts of Lewis and Brønsted acid sites on metal oxides from NH3 adsorption equilibrium: Case of TiO2 based solids

Giraud

Geantet²,

Guilhaume³

et al. 2021

Catalysis Today

View full text Add to dashboard Cite

The present study is dedicated to the development of an original method f or the measurement of the individual amounts QASi of the acid sites ASi (acidity of Le wis and Brønsted) present on three TiO2 based solids of increasing composition compl exity: TiO2-P25, 6% WO3/TiO2-P25 and a sulfated 0.7% V2O5/9% WO3/TiO2 NH3-SCR catalyst. The method is based on quantitative characterizations of the NH3 adsor ption equilibrium (adsorption temperature Ta and pressure Pa) by the association of (a) the AEIR method providing the individual coverage qASi(Ta, Pa) of the adsorbed NH3 species on the ASi sites and (b) the total amount (in µmol/g) of the adsorbed NH3 spec ies: QTNH3(Ta, Pa) by using a mass spectrometer. For a solid having n types of ASi si tes, the QASi values are obtained from the numerical solution of linear equation system s (with at least n equation) obtained considering that QTNH3(Ta, Pa) is equal to the su m of the contribution of each adsorbed NH3 species: QASi qASi(Ta, Pa).This imposes the measurement of at least n QTNH3(Ta, Pa) in a Ta range preventing the contributio n of parallel surface processes (i.e NH3 oxidation). On TiO2-P25, n= 3 (two Lewis and one weak Brønsted acid sites) and the QASi amounts are ob tained from three QTNH3(Ta, Pa) values. The others solids having two Lewis (L1 and L 2) and two Brønsted (B1 and B2) acid sites impose a series of m measurements of QT NH3(Ta, Pa) with m>> n: the QASi are obtained by optimization between theoretical an d experimental QTNH3(Ta, Pa) curves such as 109, 202, 70 and 130 µmol/g for QL2, QL1, QB2 and QB1 respectively of 0.7% V2O5/9% WO3/TiO2. It is shown that these fo ur amounts of sites permit to conclude that the L2 Lewis acid site is the one forming the pivotal NH3ads-L2 species of the reaction by using nitrogen mass balances between the amounts of a dsorbed NH3 species and the N2 production in the presence of NO.

show abstract

Applicability of V2O5-WO3/TiO2 Catalysts for the SCR Denitrification of Alumina Calcining Flue Gas

Cited by 16 publications

References 52 publications

Low-Temperature Selective Catalytic Reduction of NO with NH3 over Natural Iron Ore Catalyst

Low-Temperature Selective Catalytic Reduction of NO with NH3 over Natural Iron Ore Catalyst

Comparision on the Low-Temperature NH3-SCR Performance of γ-Fe2O3 Catalysts Prepared by Two Different Methods

Individual amounts of Lewis and Brønsted acid sites on metal oxides from NH3 adsorption equilibrium: Case of TiO2 based solids

Contact Info

Product

Resources

About