Amount Of Surface Acid Sites Research Articles

Elaborating the improving SO2 resistance mechanism of CeWTi catalysts through framework confined ordered mesoporous structures for low-temperature NH3-SCR reaction

It is still a significant challenge that enhancing SO2 tolerance on the Ce-based catalyst in NH3-SCR reaction at low temperature. In this paper, an ordered mesoporous Ce-W-Ti-E catalyst with a framework confined structure had been constructed. The active components were directly constrained in the ordered mesoporous TiO2 structure, forming the framework confined ordered mesoporous structure. The ordered mesoporous structures in the framework structure provided better specific surface area and abundant active sites for the catalyst. In addition, the confinement effect of the framework structure enhanced the interaction between Ce, W and Ti, thus speeding up the electron transfer efficiency and enhancing the redox capacity of the catalyst. Furthermore, the introduction of W also supplemented a large amount of surface acid sites, which can inhibit the adsorption of SO2 on the catalyst surface, reduce the deposition of sulfate and well protect the active sites from SO2 attack with the help of special confinement effect. Therefore, the framework confined structure Ce-W-Ti-E catalyst in the whole process of SCR showed a wide operating temperature window, better stability and strong sulfur resistance, thus extended the catalyst lifetime in the NH3-SCR process.

CO oxidation over PdOσ/Fe1-xWxOy catalysts and their SO2 resistance at relatively low temperature

Efficient sulfur-tolerant catalysts for purification in sulfur-containing steel sintering flue gas remain a severe challenge. Herein, a series of Fe2O3 modified by WO3-supported PdOσ was fabricated to make progress in this issue. WO3 decoration decreases Pd dispersion but significantly enhances the sulfur resistance of PdOσ/Fe2O3 for CO catalytic oxidation. Typically, at an SO2 concentration as high as 1000 ppm, the optimal PdOσ/Fe0.6W0.4Oy can keep its activity with a CO conversion of 90% even at relatively low temperatures (175 °C) for 20 h, which was superior to most reported catalysts. As evidenced by systematical surface properties and kinetic analysis, this accepted sulfur tolerance was closely related to the enhanced amount of surface acid sites and the formation of a new phase of FeWO4 from the strong interaction of FeOx and WO3, which could suppress SO2 adsorption and decrease the deposition of the undesirable sulfate (S6+). Additionally, PdO2 (4+) appears to be more resistant to sulfur than PdO (2+), probably due to the latter palladium species being more likely to react with sulfur. Also, WO3 modification induced the chemical state of sulfur component changing from S6+ to S4+, thereby preserving PdO2 (4+) catalytic activity species and showing remarkable performance of sulfur tolerance.

Development of a Ru catalyst supported on HY zeolite for the oxidative decomposition of NH3 triggered at room temperature

On-site hydrogen production from the oxidative decomposition of NH3 with a catalyst is highly required in the countryside where external heat is hardly supplied. In this study, Ru-based zeolite catalysts were prepared by impregnation and subsequent washing using RuCl3·3H2O and HY zeolite or H-MOR zeolite for the oxidative decomposition of NH3. The H-MOR-supported Ru catalyst could not be self-heated by feeding 80% NH3/20% O2 to the catalyst bed at room temperature. By contrast, the HY-supported Ru catalyst underwent self-heating to approximately 773 K upon feeding the reactants owing to the heat released by NH3 adsorption and oxidation, leading to excellent performance for the oxidative decomposition of NH3 during five cycles of start-up tests. Characterization results indicated that the Cl-free Ru/HY catalyst exhibited self-heating due to the presence of small well-dispersed Ru metal particles and a large amount of surface acidic sites.

Unveiling geometric and electronic effects of Pt species on water-tolerant Pt/ZSM-5 catalyst for propane oxidation

Si/Al ratio of ZSM-5 affecting Pt/ZSM-5 catalyst water-tolerance has been investigated for propane oxidation. Under wet condition (5 % H2O), it is found that Pt/ZSM-5 (18) catalyst contains both irreversible and reversible deactivation Pt active sites; Pt/ZSM-5 (130) and Pt/ZSM-5 (500) catalysts have only reversible deactivation Pt active sites; all the Pt active sites in the Pt/ZSM-5 (1200) catalyst are water tolerant. It is further found that the Si/Al ratio of ZSM-5 determines the geometrical and electronic states of Pt particles, and amount of surface acid sites on catalysts, thereby affecting the water tolerance of Pt/ZSM-5 catalyst. Low Si/Al ratio of ZSM-5 benefits to anchor the Pt species and form small Pt particles, but Pt particle with small size and more oxidized state Pt species (Ptδ+) on Pt/ZSM-5 (18) is easily poisoned by H2O. More Pt0 species generating on large Pt particle during propane oxidation reaction and low surface acid sites on Pt/ZSM-5 (1200) catalyst are responsible for its high water tolerance.

Synergistic removal of NO and soot by Fe-W-Zr-ZSM-5 catalysts in a wide temperature window

Obtaining the synergistic catalytic removal of NO and soot is a highlight topic as both NO and soot are the main pollutants from diesel engine. However, synergistic catalytic removal is still very difficult because the temperature window varies with the traditional SCR catalyst of NO at narrow temperature of 300–450 ℃ and the oxidation temperature of soot at high temperature of 500–700 ℃. Therefore, based on W-Zr-ZSM-5 catalyst, a series of M-W-Zr-ZSM-5 (M = Cu, Fe or Nb) catalysts were prepared by sol–gel method to investigate the synergistic catalytic removal of NO and soot, which emitted from diesel engine at the same time. The results showed that Fe-W-Zr-ZSM-5 catalyst exhibited the best NH3-SCR reaction activity and oxidizing performance of soot among the catalysts, with more than 90 % NO conversion in the temperature range of 320 ℃ to 580 ℃ and completely oxidization of soot in the temperature range of 432 ℃ to 543 ℃. The results of XRD, BET, XPS and Raman spectrum indicated that there was strong interaction between W and Fe, promoting the formation of W5+ and W = O species, thereby increasing the content of chemisorbed oxygen, the amount of surface acid sites and redox capacity of the catalysts. Meanwhile, the redox capacity of Fe-W-Zr-ZSM-5 was responsible for the improvement of NH3-SCR activity and the oxidation of soot at low temperature. Fe-W-Zr-ZSM-5 catalyst demonstrated to be a promising material to synergistic remove NO and soot.

Ga-Doped MgAl2O4 Spinel as an Efficient Catalyst for Ethane Dehydrogenation to Ethylene Assisted by CO2

A series of Ga-doped MgAl2O4 spinels was prepared via a simple coprecipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption, X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) techniques. Their acidity and basicity were measured by NH3-temperature-programmed desorption (TPD) and CO2-TPD, respectively. These spinel catalysts exhibit good catalytic performance toward ethane dehydrogenation after Ga-doping either in the absence or in the presence of CO2. Their dehydrogenation activity is positively associated with the amount of surface acid sites of medium-strong strength, confirming that the coordinatively unsaturated Ga3+ cations are the active species in the reaction. The introduction of CO2 shows an obvious promoting effect on the dehydrogenation activity of the catalysts because of their high activity for the reverse water-gas shift reaction along with an improved catalyst stability, as a result of the coexisting Boudouard reaction. An ethane conversion of 43% and ethylene selectivity of 92% can be achieved, and the activity and selectivity of this type of catalysts can be fully recovered by regeneration through calcination in flowing air.

Environmental-friendly production of FeNbTi catalyst with significant enhancement in SCR activity and SO2 resistance for NOx removal

An environmental-friendly FeNbTi catalyst with different Nb doping was investigated for NH3-SCR reaction at low temperature, which exhibited excellent activity and tolerance to SO2 and H2O poisoning. A series of characterization were used to investigate the reasons for the high activity and SO2 resistance of the catalyst before and after Nb modification, such as BET, XRD, XPS, H2-TPR, O2-TPD, NH3-TPD, NO-TPD and DRIFT. XRD and XPS results displayed that the doping of Nb could promote the speciation transformation of Fe2O3 from crystalline to amorphous phase and more chemisorbed oxygen species generated. In addition, NH3-TPD and NO-TPD results suggested that the amount of surface acid sites and NO chemisorption increased after Nb doping, and the adsorption and oxidation of NH3 or NO improved through DRIFT analysis. All these factors contributed to the outstanding SCR performance and strong resistance to SO2 and H2O.

Insight into the effect of carrier on N2O formation over MnO2/MOx (M = Al, Si and Ti) catalysts for selective catalytic reduction (SCR) of NOx with NH3

The problems of easily inactivated by SO2 poisoning and high N2O formation for MnOx based catalysts hinder its application in selective catalytic reduction (SCR) of NOx with NH3. The SO2 poisoning mechanism has been well demonstrated, but the N2O formation mechanism was still controversial due to previous limited study. Herein, MnO2 supported on MOx (Mn/M, M = Al, Si and Ti) were prepared by wet impregnation method to investigate the carrier effect on the formation of N2O. Although all of selected supports had a large amount of surface acid sites, only forming strong active-support interaction can separate the activation sites of NH3 and NO + O2. Accordingly, the activation of NH3 and NO + O2 on MnTi was respectively occurred on TiO2 and MnO2, but both NH3 and NO + O2 was activated on MnO2 over MnAl and MnSi samples. The over-activation (NH2 dissociated into NH) of NH3 would be effectively inhibited when NH3 activation was occurred on TiO2, thus it can significantly suppress the formation of N2O. In contrast, the NH3 species would sharply decompose into NH on MnO2 and then lead to the high amount of N2O. Finally, we proposed some methods that might effectively improve the selectivity of MnOx-based catalysts.

A novel vapor-phase catalytic synthetic approach for industrial production of 1,1,1,3,3,3-hexafluoroisopropyl methylether

1,1,1,3,3,3-Hexafluoroisopropylmethyl ether (HFE-356mmz) is an important substitute for chlorofluorocarbons and hydrochlorofluorocarbons due to its zero ozone depletion potential and low global warming potential. However, mass production of HFE-356mmz remains a long-standing challenge. Herein, we applied metal fluorides as catalysts in the methylation of 1,1,1,3,3,3-hexafluoroisopropanol to produce HFE-356mmz for the first time.The catalyst not only improves the synthetic efficiency, but also makes the reaction solvent-free.The pollution-free, recyclable, and continuous synthetic process enables industrial production of HFE-356mmz. To optimize the synthetic efficiency, a series of metal fluorides (AlF3, MgF2, CaF2, SrF2, and BaF2) was used, among which MgF2 exhibited the highest activity. Through careful examination of each metal fluoride, it was found that the activity of the catalyst was determined by co-operative action of the surface acid–base properties and the total amount of surface acid sites. Based on these results, a rational mechanism for the vapor-phase methylation was proposed.

A Sulfonated Porous Polymer as Solid Acid Catalyst for Biofuel Synthesis and Chemical Fixation of CO2

AbstractDeforestation and uncontrolled emission of carbon dioxide (CO2) through abundant use of fossil fuels result global warming. This serious threat to the atmosphere has deeply motivated the researchers to develop new strategies for chemical fixation of CO2 and biofuel synthesis. Here we report the sulfonated porous polytriphenylamine (SPPTPA‐1, BET surface area of 664 m2 g−1, pore volume 0.386 cc g−1) as an efficient heterogeneous catalyst for the synthesis of cyclic carbonates via CO2 fixation into epoxides. SPPTPA‐1 catalyst contains pores with dimension of 1.8‐2.0 nm, which produced a H1 type hysteresis loop in N2 adsorption/desorption isotherm. The porous catalyst is thermally stable upto 196 °C. The synthesized SPPTPA‐1 catalyst contains large amount of surface acidic sites. Further, it catalyzes the esterification reaction of levulinic acid, long chain fatty acids and dicarboxylic acids due to presence of its acidic sites. This solid acid catalyst SPPTPA‐1 showed excellent recycling efficiency upto 5 times in all these demanding reactions.

The promotional effect of SO42− on N2 selectivity for selective catalytic oxidation of ammonia over RuO2/ZrO2 catalyst

The promoting effects of SO42− on N2 selectivity for selective catalytic oxidation (SCO) of ammonia to nitrogen over RuO2/ZrO2 catalyst were systematically investigated. The catalysts were measured by different characterization methods (BET, XRD, TEM, NH3–TPD and in situ DRIFTS). The results showed that the introduction of SO42− into RuO2/ZrO2 presented obvious effects on the structure, surface acidity and N2 selectivity of RuO2/ZrO2. The introduction of SO42− obviously increased the amount of surface acid sites, which could promote the adsorption of ammonia species and prevent the excessive oxidation of ammonia to NOx, improving the N2 selectivity dramatically. The DRIFTS results confirmed that the SCO of ammonia over RuO2/ZrO2–SO42− followed the in situ selective catalytic reduction of NOx (i-SCR) mechanism, involving NH3 oxidation to NO species and –NH2 reacted with NO to form the main product N2. The presence of SO42− not only increased the surface acid sites of the catalyst, but also inhibited the production of nitrate species, which was beneficial to improve the N2 selectivity.

Superior performance and resistance to SO2 and H2O over CoOx-modified MnOx/biomass activated carbons for simultaneous Hg0 and NO removal

A series of CoOx modified MnOx/biomass activated carbons (CoMn/BACs) prepared by the ultrasound-assisted impregnation method were employed for the simultaneous removal of NO and Hg0 from simulated coal-fired flue gas for the first time. The physicochemical properties of such samples were characterized by XRD, BET, SEM, TEM, NH3-TPD, H2-TPR, FTIR, TG and XPS. 15%CoMn/BAC exhibited preferable performance for NO and Hg0 removal in a wide temperature range from 160 to 280 °C, and it yielded prominent NO removal efficiency (86.5%) and superior Hg0 removal efficiency (98.5%) at 240 °C. The interaction between NO removal and Hg0 removal lessened corresponding separate efficiency, the adverse effect of NH3 on Hg0 removal could not be offset by promotional influences of NO and O2. Compared with 15%Mn/BAC, the addition of CoOx with suitable amount into 15%CoMn/BAC could contribute to the synergistic effect between MnOx and CoOx, resulting in the increase of BET surface area and surface active oxygen species as well as Mn4+ concentration, the enhancement of redox ability and the strength or amount of surface acid sites, restraining the crystallization of MnOx, which might be responsible for the improvement of catalytic performance and resistance to SO2 and H2O. Additionally, the hydrophobic property of BAC further strengthened H2O tolerance. The results of stability and recyclability tests indicated that 15%CoMn/BAC possessed a promising application potential for NO and Hg0 simultaneous removal at low temperature.

Thermal stability of Si-doped V2O5/WO3–TiO2 for selective catalytic reduction of NOx by NH3

The selective catalytic reduction of NOx with NH3 (NH3-SCR) is a very effective technology to control the emission of NOx, and the thermal stability of NH3-SCR catalyst is very important for removal of NOx from diesel engines. In this work, V2O5/WO3–TiO2 (VWT) and SiO2-doped V2O5/WO3–TiO2 (VWTSi10) catalysts were prepared by impregnation method and characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Raman, temperature programmed reduction by hydrogen (H2-TPR), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption by ammonia (NH3-TPD). The doping of SiO2 promotes the thermal stability of V2O5/WO3–TiO2 for NH3-SCR significantly. After calcination at 650 °C for 50 h, the operation window of 10% SiO2-doped V2O5/WO3–TiO2 is 220–480 °C, while the maximum NOx conversion on V2O5/WO3–TiO2 is about 77%. The presence of SiO2 obviously blocks the transformation of TiO2 from anatase to rutile and stabilizes the dispersion of VOx and WO3 on the surface. It is available for the existence of V4+ and the amount of surface acid sites increases, which inhabits the NH3 oxidation at the high temperature range and promotes NH3-SCR activity.

Gas phase dehydration of glycerol to acrolein over Cs2.5H0.5PW12O40/Zr-MCM-41 catalysts prepared by supercritical impregnation

The Cs2.5H0.5PW12O40/Zr-MCM-41 samples were synthesized by supercritical impregnation and investigated in gas phase dehydration of glycerol to acrolein. The Cs2.5H0.5PW12O40/Zr-MCM-41 sample prepared by conventional wet impregnation was also examined for comparison. The catalysts were studied using X-ray diffraction, N2 adsorption, the temperature-programmed desorption of ammonia, infrared spectroscopy after pyridine adsorption, thermogravimetric analysis, 31P MAS NMR, inductively coupled plasma-atomic emission spectrometry and CHNS analysis. According to the results of characterization, the preparation condition of supercritical carbon dioxide facilitated the improvement of the Cs2.5H0.5PW12O40 dispersion on Zr-MCM-41. The specific surface area, pore volume and pore size were increased, and the total amount of surface acid sites and the ratio of Brønsted acid sites to total acidity were increased. The strong acid sites were transformed into the weak and medium acid sites. The formation of coke was retarded. Therefore, the glycerol conversion, acrolein selectivity and yield, and the catalytic stability were obviously improved.

Hydrogen production via steam reforming of ethylene glycol over Attapulgite supported nickel catalysts

Steam reforming of ethylene glycol was investigated over Ni-based catalysts supported on Attapulgite (ATP; originating from Jiangsu (JS), Anhui, and Gansu (GS) provinces in China). N2 adsorption–desorption, XRD, FTIR, H2-TPR, NH3-TPD, SEM, and TEM-EDS measurements were performed to analyze the catalyst properties. The results revealed that Ni/ATPGS had the largest particle size (17.9 nm) and the highest reductive degree (98.0%). Consequently, Ni/ATPGS showed the highest ethylene glycol conversion (97.2%) during the first 4 h of reaction. However, this catalyst showed the lowest H2 yield (71.2%), possibly owing to large Ni particle sizes as well as ample surface acidic sites and acidity, leading to a high selectivity toward CH4 (20.8%) and C2H4 (2.2%). In contrast, Ni/ATPJS presented the highest H2 yield (89.8%) owing to it having the smallest Ni particle sizes and lowest amount of surface acidic sites. Additionally, this catalyst showed the highest stability over 8 h of reaction. An examination of the spent catalysts revealed that Ni/ATPJS possessed excellent antisintering and coking properties.

Carbonylation of methanol to methyl acetate over Cu/TiO2-SiO2 catalysts: Influence of copper precursors

In the present study, three kinds of copper/titania-silica mixed oxides (Cu/TS) catalysts were prepared using copper chloride, copper nitrate, and copper acetate as copper precursors by the sol-gel method. The catalytic performance was tested in the vapor phase carbonylation of methanol free of halide. The characterization results showed that the interaction between copper and support was the strongest on the 10Cu/TS (Cl) catalyst, leading to the highest copper dispersion and the most surface Cu+ species. As a result, the 10Cu/TS (Cl) catalyst obtained the largest absorption capacity of CO and the maximum amount of Lewis acid sites. The catalytic performance results showed that the space time yield (STY) of methyl acetate (MA) was positively correlated with the content of surface Cu+ species and the specific surface area of the Cu+ cations (SCu(I)). Therefore, the 10Cu/TS (Cl) catalyst obtained the highest STYMA of 1.619 mol/h.kgcat. Moreover, the STYMA per Cu+ site was inversely proportional to the copper particle size, indicating that the carbonylation of methanol to MA is a structure-sensitive reaction. And the methanol conversion was positively correlated with the amount of surface acid sites. Furthermore, the active sites for the synthesis of methyl formate and dimethyl ether were also studied.

Eu-Mn-Ti mixed oxides for the SCR of NOx with NH3: The effects of Eu-modification on catalytic performance and mechanism

A series of highly active de-NOx catalysts, Eu-modified MnOx-TiO2 (MnTiEu), was prepared by an inverse co-precipitation method. Their physiochemical properties were investigated by XRD, TEM, EDS, BET, XPS and H2-TPR in detail, and their catalytic activities were evaluated by the selective catalytic reduction (SCR) of NO with NH3. The results showed that the introduction of Eu with proper amount into MnOx-TiO2 can effectively restrain the crystallization process of MnOx and TiO2, enhance specific surface area, increase the concentration of both surface Mn4+ and chemisorbed oxygen species, improve the stability of Mn4+ and Mn3+, reduce the amount of surface acid sites, enhance the strength of surface acid sites. The obtained MnTiEu-0.3 catalyst (the molar rate of Eu/Mn was 0.3 and the mole rate of Mn/Ti was 0.1) exhibited a 100% NOx conversion activity in a wide temperature window from 180 to 390°C and a 100% N2 selectivity from 120 to 390°C under a high space velocity of 36,000h−1. Furthermore, MnTiEu-0.3 catalyst presented stronger resistance to concurrent H2O and SO2 poison in comparison with MnOx-TiO2 catalyst without Eu addition. In-situ DRIFT spectra suggested that NH3 can be adsorbed on both Lewis and Brønsted acid sites. For MnOx-TiO2 catalyst, both coordinated NH3 species on Lewis acid sites and NH4+ species on Brønsted acid sites can react with gas-phase NO following E-R mechanism. As regards MnTiEu-0.3, the NH3-SCR of NO follows both Eley-Rideal and Langmuir-Hinshelwood mechanisms, in which the Eley-Rideal mechanism is predominated.

Acid pretreatment effect on the physicochemical property and catalytic performance of CeO2 for NH3-SCR

A series of CeO2 pretreated with different acids (i.e., CH3COOH (HAc), HNO3, HCl, H3PO4, and H2SO4) were prepared with the purpose of exploring the influence of acid pretreatment on the physicochemical property and catalytic performance of CeO2 for NH3-SCR. And then, these catalysts were characterized by means of XRD, Raman, N2-physisorption, H2-TPR, NH3-TPD, in situ DRIFTS, XPS, and NH3-SCR reaction. The obtained results indicate that different acids pretreatment has different influence on the structure, texture, reduction behavior, surface acidity, surface property, and catalytic performance of CeO2. Especially, the sample pretreated by H2SO4 (i.e., CeO2-S catalyst) exhibits the best catalytic performance for NH3-SCR reaction at high temperature among these catalysts due to the largest amount of surface acid sites (especially B acid sites) and Ce3+, as well as the increase of defect sites (such as oxygen vacancy) and the most abundant reducible species. Furthermore, CeO2-S catalyst also exhibits excellent catalytic performance (i.e., above 80% NO conversion) during the whole test of H2O+SO2 resistance, which indicates that it has the potential to be applied in the practical denitration process.

Preparation of NiAlO x and NiSiO x Complex Oxides with High Surface Areas for the Isomerization Reactions of 1-Hexene

The NiAlO x and NiSiO x complex oxides with high surface areas were prepared by the co-precipitation method through the control of acidity of solutions. Nickel species were found to be highly dispersed in these complex oxides and a remarkable feature was that the incorporation of large amount of nickel cations into SiO2 generated the great amount of surface acid sites. Upon the sulfidation by CS2, the sulfided catalysts were found to be highly active for the conversion of 1-hexene to different products formed from the three main competitive reactions (skeletal isomerization, double bond isomerization and hydrogenation of all hexenes). The high yield of skeletal isomerization of 1-hexene on a sulfided NiSiO x (55 %) could be attributed to the high density of acid sites for the adsorption of 1-hexene as well as the low hydrogenation activity of nickel species on this catalyst. In contrast, the high yields of direct hydrogenation and double bond isomerization of 1-hexene on the sulfided NiAlO x might be due to the high hydrogenation activity of nickel species as well as the surface acidity and basicity on the catalyst. The sulfided NiAlO x and NiSiO x complex oxides were highly active for the conversion of 1-hexene to different products. The high yield of skeletal isomerization of 1-hexene on the sulfided NS10 (55 %) could be attributed to the high density of acid sites for the adsorption of 1-hexene.

Promotional Effect of Ce on Iron-Based Catalysts for Selective Catalytic Reduction of NO with NH3

A series of Fe–Ce–Ti catalysts were prepared via co-precipitation method to investigate the effect of doping Ce into Fe–Ti catalysts for selective catalytic reduction of NO with NH3. The NO conversion over Fe–Ce–Ti catalysts was considerably improved after Ce doping compared to that of Fe–Ti catalysts. The Fe(0.2)–Ce(0.4)–Ti catalysts exhibited superior catalytic activity to that of Fe(0.2)–Ti catalysts. The obtained catalysts were characterized by N2 adsorption (BET), X-ray diffraction (XRD), temperature programmed reduction (H2-TPR), temperature programmed desorption (NH3-TPD), Fourier transform infrared (FT-IR) spectrophotometry, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The data showed that the introduction of Ce results in higher surface area and better dispersion of active components on the catalyst surface and enhances the amount of surface acid sites. The interactions between Fe and Ce species were found to improve the redox ability of the catalyst, which promotes catalytic performance at low temperature. The XPS results revealed that Fe3+/Fe2+ and Ce4+/Ce3+ coexisted on the catalyst surface and that Ti was in 4+ oxidation state on catalyst surface. Ce doping increased the atomic ratio of Fe/Ti and Ce/Ti and enhanced the surface adsorbed oxygen species. In addition, Fe(0.2)–Ce(0.4)–Ti catalyst also showed better tolerance to H2O and SO2 and up to 92% NO conversion at 270 °C with 200 ppm SO2 added over 25 h, which suggests that it is a promising industrial catalyst for mid-low temperature NH3–selective catalytic reduction (SCR) reaction.