Enhancement of Low-Temperature Catalytic Activity over a Highly Dispersed Fe–Mn/Ti Catalyst for Selective Catalytic Reduction of NO_x with NH₃

Abstract

A novel Fe2O3–MnO2/TiO2 catalyst was synthesized using a conventional impregnation method assisted with ethylene glycol and used for NH3–SCR. The catalyst exhibited superior low-temperature activity over a broad temperature window (100–325 °C), low apparent activation energy, and excellent sulfur-poisoning resistance. The characterization results revealed that the catalyst was greatly dispersed with smaller particles, and the partial doping of Fe into the TiO2 lattice thereby led to the formation of the Fe–O–Ti structure, which could strengthen the electronic inductive effect and increase the ratio of surface chemisorption oxygen, resulting in the enhancement of NO oxidation and favoring the low-temperature SCR activity via a “fast SCR” process. The in situ FTIR analysis showed that the NO x adsorption capacity was significantly improved due to the desired dispersion property, further helping both the SCR activity and reaction rate at low temperatures. The present work confirmed that more active sites can be provided on the catalyst surface by modifying the dispersity.

Simultaneous removal of SO2 and NO by CO reduction over prevulcanized Fe2O3/AC catalysts

“…Moreover, the stability of Fe 2 O 3 [10]/AC was further investigated at 280 °C over a period of 40 h (Figure ). It shows that the catalyst was stable within 30 h and only slight decreases in desulphurization and denitrification efficiency were observed up to 40 h. Therefore, the carbon based catalysts exhibited superior low‐temperature activity at low temperatures …”

Preparation of Mesoporous Mn–Ce–Ti–O Aerogels by a One-Pot Sol–Gel Method for Selective Catalytic Reduction of NO with NH3

“…Materials 2020, 13, x FOR PEER REVIEW whereas another six peaks belonged to Ce 4+ species [14,38]. Two peaks, at ~464.5 eV and ~458.7 eV, were observed for the XPS spectra of Ti 2p, as shown in Figure 5c, which were attributed to Ti 2p3/2 and Ti 2p1/2, respectively, representing the characteristic Ti 4+ species [11,14]. The XPS spectra of O1s in Figure 5d exhibited two doublet peaks at 531.1-531.8 eV and 529.3-529.8 eV, which were assigned to the surface chemisorbed oxygen (denoted as Oα) such as defect-oxide (O2 2− or O − ) and hydroxyl groups, and the lattice oxygen O 2− (denoted as Oβ), respectively [11,41].…”

“…The XRD patterns of the MCTO-0, MCTO-400, MCTO-500, MCTO-600, and MCTO-700 are shown in Figure 2. The diffraction peaks at 25.3°, 37.8°, 38.6°, 48.1°, 51.0°, 55.1°, 62.7°, 68.9°, 70.3°, and 75.3° were observed for MCTO-0 sample, which were attributed to anatase TiO2 (JCPDS 21-1272) [11]. The characteristic peaks of the Mn3O4 phase (JCPDS 24-0734) at 28.9°, 32.3°, 38.0°, and 59.8° and the Mn2O3 phase (JCPDS 33-0900) at 32.3°, 35.6°, and 62.3° were detected for the calcined products [38].…”

“…At present, many denitration technologies have been developed to remove NO x to meet stringent legislation requirements, such as selective catalytic reduction (SCR) [1][2][3][4][5][6], selective non-catalytic reduction (SNCR) [7], and absorption [8], among which the selective catalytic reduction with NH 3 (NH 3 -SCR) is one of the most promising approaches for NO x removal owing to its high denitration efficiency and relatively low cost. Vanadium-titanium catalysts are the most commonly used catalysts currently in industry to remove NO x from stationary sources, including V 2 O 5 -WO 3 /TiO 2 and V 2 O 5 -WO 3 (MoO 3 )/TiO 2 [9][10][11][12]. However, to satisfy the working conditions of the V-based catalysts, the current SCR denitration device has to be installed upstream of the electrostatic precipitator and the desulfurization device to avoid the deactivation of catalysts by high-concentration fly ash, alkali metals, and SO 2 [13], to increase the life time of the catalysts and to reduce the operating costs of denitration.…”

Mn Modified Ni/Bentonite for CO2 Methanation

“…In general, the addition of a small amount of rare earth or transition metal could effectively reduce the catalytic hydrogenation reaction temperature, i.e., Ni 2+ could be partially substituted with Co 3+ ions to form a Ni-Co spinel solid solution, and is vital for CO oxidation [27]; Fe modified Mn/TiO 2 catalysts showed distinguished catalytic activities in the NH 3 -SCR reaction [28]; the addition of La and Mn additives facilitated the dispersion of Ni species, and increased the syngas methanation activities of Ni catalysts [29]. Among them, transition metal Mn exhibited the properties of the adjusted d-electron structure and could improve the surface area of the active metal, as well as the metal dispersion on the support [30].…”