Advanced MnOx/TiO2 Catalyst with Preferentially Exposed Anatase {001} Facet for Low-Temperature SCR of NO

A High-Performance Mn/TiO2 Catalyst with a High Solid Content for Selective Catalytic Reduction of NO at Low-Temperatures

Mn/TiO2 catalysts with varying solid contents were innovatively prepared by the sol-gel method and were used for selective catalytic reduction of NO at low temperatures using NH3 (NH3-SCR) as the reducing agent. Surprisingly, it was found that as the solid content of the sol increased, the catalytic activity of the developed Mn/TiO2 catalyst gradually increased, showing excellent catalytic performance. Notably, the Mn/TiO2 (50%) catalyst demonstrates outstanding denitration performance, achieving a 96% NO conversion rate at 100 °C under a volume hourly space velocity (VHSV) of 24,000 h-1, while maintaining high N2 selectivity and stability. It was discovered that as the solid content increased, the catalyst's specific surface area (SSA), surface Mn4+ concentration, chemisorbed oxygen, chemisorption of NH3, and catalytic reducibility all improved, thereby enhancing the catalytic efficiency of NH3-SCR in degrading NO. Moreover, NH3 at the Lewis acidic sites and NH4+ at the Bronsted acidic sites of the catalyst were capable of reacting with NO. Conversely, NO and NO2 adsorbed on the catalyst, along with bidentate and monodentate nitrates, were unable to react with NH3 at low temperatures. Consequently, the developed catalyst's low-temperature catalytic reaction mechanism aligns with the E-R mechanism.

Design of Ca-type todorokite catalysts with highly active for the selective reduction of NOx by NH3 at low temperatures

Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NOx by NH3 (NH3-SCR) for the first time. Compared with the Na-type manjiroite prepared by the same method, the todorokite catalysts with different Mn/Ca ratios showed greatly improved catalytic activity for NOx reduction. Among them, Mn8Ca4 catalyst exhibited the best NH3-SCR performance, achieving 90% NOx conversion within temperature range of 70-275°C and having a high sulphur resistance. Compared to the Na-type manjiroite sample, Ca-type todorokite catalysts possessed an increased size of tunnel, resulting in a larger specific surface area. As increased the amounts of Ca doping, the Na content in Ca-type todorokite catalysts significantly decreased, providing larger amounts of Brønsted acid sites for NH3 adsorption to produce NH4+. The NH4+ species were highly active for reaction with NO + O2, playing a determining role in NH3-SCR process at low temperatures. Meanwhile, larger amounts of surface adsorbed oxygen contained over the Ca-doping samples than that over Na-type manjiroite, promoting the oxidation of NO and fast SCR processes. Over the Ca-type todorokite catalysts, furthermore, nitrates produced during the flow of NO + O2, were more active for reaction with NH3 than that over Na-type manjiroite, benefiting the occurrence of NH3-SCR process. This study provides novel insights into the design of NH3-SCR catalysts with high performance.

Revealing the Excellent Low-Temperature Activity of the Fe1-xCexOδ-S Catalyst for NH3-SCR: Improvement of the Lattice Oxygen Mobility

The development of selective catalytic reduction catalysts by NH₃(NH₃-SCR) with excellent low-temperature activity and a wide temperature window is highly demanded but is still very challenging for the elimination of NO_x emission from vehicle exhaust. Herein, a series of sulfated modified iron-cerium composite oxide Fe_1-xCe_xO_δ-S catalysts were synthesized. Among them, the Fe_0.79Ce_0.21O_δ-S catalyst achieved the highest NO_x conversion of more than 80% at temperatures of 175-375 °C under a gas hourly space velocity of 100000 h^-1. Sulfation formed a large amount of sulfate on the surface of the catalyst and provided rich Brønsted acid sites, thus enhancing its NH₃ adsorption capacity and improving the overall NO_x conversion efficiency. The introduction of Ce is the main determining factor in regulating the low-temperature activity of the catalyst by modulating its redox ability. Further investigation found that there is a strong interaction between Fe and Ce, which changed the electron density around the Fe ions in the Fe_0.79Ce_0.21O_δ-S catalyst. This weakened the strength of the Fe-O bond and improved the lattice oxygen mobility of the catalyst. During the reaction, the iron-cerium composite oxide catalyst showed higher surface lattice oxygen activity and a faster replenishment rate of bulk lattice oxygen. This significantly improved the adsorption and activation of NO_x species and the activation of NH₃ species on the catalyst surface, thus leading to the superior low-temperature activity of the catalyst.

Effects of Preparation Methods of Pd Supported on (001) Crystal Facets Exposed TiO2 Nanosheets for Toluene Catalytic Combustion

A series of TiO2 nanosheets-supported Pd catalysts were individually prepared by impregnation, deposition–precipitation, photo-deposition and in situ reduction by NaBH4. For comparison, Pd supported on P25 was prepared by the impregnation method. The experimental results show that the catalytic efficiency of the catalyst prepared with titanium dioxide nano sheet as the support is higher than that of the catalyst supported with P25. Its excellent properties are as follows: The resulting sample indicates that TiO2 nanosheets-supported Pd catalyst display an improved activity than Pd/P25, whose temperature of 100% complete conversion of toluene decreased by 40 ℃ at the most. The Pd particles on the catalyst synthesized by the light deposition method and the NaBH4 reduction method are more obvious, while the Pd particles on the catalyst synthesized by the immersion method and the deposition–precipitation method are less obvious, which shows that the latter two methods are more conducive to the dispersion of Pd. The good catalytic activity may be due to the better exposed mirror and dispersion of titanium dioxide nanosheets. This is mainly related to the exposed crystal plane of the nanosheet TiO2 (001), which made it easier to form the oxygen vacancy. Moreover, among all of the TiO2 nanosheets-supported Pd catalysts, Pd/TiO2 NS (TiO2 NS means TiO2 nanosheets) prepared by the impregnation method show the highest catalytic activity. The XRD results show that Pd prepared by impregnation is more dispersed and smaller. This is due to PdO being dispersed more efficiently than the others, leading to more Pd active sites.

Engineering yolk-shell MnFe@CeOx@TiOx nanocages as a highly efficient catalyst for selective catalytic reduction of NO with NH3 at low temperatures

To broaden the reaction temperature range and improve the H₂O-resistance of manganese-based catalysts, yolk-shell structured MnFe@CeO_x@TiO_x nanocages were prepared. The CeO₂ shell could effectively increase the oxygen vacancy defect sites, and the TiO₂ shell could remarkably improve the surface acid sites. Combining the advantages of the two shells could effectively solve the above questions. The catalytic efficiency of the yolk-shell MnFe@CeO_x@TiO_x-40 nanocages could reach above 90% in the range of 120-240 °C, and the water resistance could reach 90% at 240 °C. On the one hand, the construction of double shells could significantly increase the proportion of active species (Mn⁴⁺, Fe³⁺, Ce³⁺ and O_ads) and the interface effect between the shell layers could effectively enhance the interaction between metal oxides. On the other hand, the construction of double shells could achieve an appropriate balance between the redox capacity of the catalyst and surface acidity. Simultaneously, in situ DRIFT spectroscopy indicated that the yolk-shell MnFe@CeO_x@TiO_x-40 nanocages mainly followed the L-H mechanism during the NH₃-SCR reaction. Finally, this double-shell structure strategy provided a new idea for constructing a Mn-based catalyst with a wide temperature window and better low-temperature water resistance.

TiO2 nanosheet supported MnCeOx: a remarkable catalyst with enhanced low-temperature catalytic activity in o-DCB oxidation

Morphology engineering was an effective strategy for 1,2-dichlorobenzene (o-DCB) oxidation. Herein, TiO₂ nanosheet supported MnCeO_x (TiMn15Ce30-NS) showed excellent catalytic activity with T_50% = 156 °C and T_90% = 238 °C, which was better than the T_50% = 213 °C and T_90% = 247 °C for TiO₂ nano truncated octahedron supported MnCeO_x (TiMn15Ce30-NTO). TiMn15Ce30-NS also exhibited enhanced water resistance (T_50% = 179 °C, T_90% = 240 °C), and good stability with the o-DCB conversion retained at 98.9% for 12 h at 350 °C. The excellent catalytic activity of TiMn15Ce30-NS could be mainly ascribed to the preferentially exposed {001} crystal plane and Ce addition which favored the higher concentration of Mn⁴⁺ and surface active oxygen, along with stronger interaction between MnO_x and CeO_x. The present results deepen the understanding of the morphology-dependent effect on o-DCB oxidation.

One-step synthesis by redox co-precipitation method for low-dimensional Me-Mn bi-metal oxides (Me=Co, Ni, Sn) as SCR DeNOx catalysts

In this research, one-step synthesis of redox co-precipitation method (using sodium lauryl sulfate, KMnO₄, and metal precursor) was well applicable in universally preparing low-dimensional Me-MnOx nanosheet catalysts with different metal doping (Me=Co, Ni, or Sn). NH₃-SCR activity was explored to the relationship with structure morphology and physio-chemical properties via the characterization techniques of SEM, XRD, XPS, H₂-TPR, and NH₃-TPD. It was found that Ni-MnOx has a relatively poor activity at low-down temperature but was improved as the reaction temperature rising. Co-MnOx presented a relatively stable catalytic activity of which the NOx conversion rate can be maintained 80~90% in a wide temperature window of 100-250 °C with relatively better N₂ selectivity. Compared with Co- or Ni-modified MnOx, Sn-MnOx catalyst has an excellent low-temperature catalytic activity (93% NOx conversion at 100 °C) that was maintained > 80% before 200 °C but with poor selectivity to N₂. Due to its nanosheet-structured solid solution structure, Sn-MnOx promoted the interaction between MnOx and SnO₂ with the increased contents of adsorbed oxygen and also the numbers of surface Lewis acid sites, which integrally promoted the NH₃-SCR reaction at low temperature and also contributed to an acceptable resistances to water and sulfur. High content of adsorbed oxygen was beneficial to improve the catalytic activity at lower temperatures, while the electron cycle interaction of different metal valence ions will play a more important role with the increase of reaction temperature.

Co- or Ni-modified Sn-MnOx low-dimensional multi-oxides for high-efficient NH3-SCR De-NOx: Performance optimization and reaction mechanism

NH₃-SCR performances were explored to the relationship between structure morphology and physio-chemical properties over low-dimensional ternary Mn-based catalysts prepared by one-step synthesis method. Due to its strong oxidation performance, Sn-MnOx was prone to side reactions between NO, NH₃ and O₂, resulting in the generation of more NO₂ and N₂O, here most of N₂O was driven from the non-selective oxidation of NH₃, while a small part generated from the side reaction between NH₃ and NO₂. Co or Ni doping into Sn-MnOx as solid solution components obviously stronged the electronic interaction for actively mobilization and weakened the oxidation performance for signally reducing the selective tendency of side reactions to N₂O. The optimal modification resulted in improving the surface area and enhancing the strong interaction between polyvalent cations in Co/Ni-Mn-SnO₂ to provide more surface adsorbed oxygen, active sites of Mn³⁺ and Mn⁴⁺, high-content Sn⁴⁺ and plentiful Lewis-acidity for more active intermediates, which significantly broadened the activity window of Sn-MnOx, improved the N₂ selectivity by inhibiting N₂O formation, and also contributed to an acceptable resistances to water and sulfur. At low reaction temperatures, the SCR reactions over three catalysts mainly obeyed the typical Elye-rideal (E-R) routs via the reactions of adsorbed l-NHx (x = 3, 2, 1) and B-NH₄⁺ with the gaseous NO to generate N₂ but also N₂O by-products. Except for the above basic E-R reactions, as increasing the reaction temperature, the main adsorbed NOx-species were bidentate nitrates that were also active in the Langmuir-Hinshelwood reactions with adsorbed l-NHx species over Co/Ni modified Mn-SnO₂ catalyst.

Converting Poisonous Sulfate Species to an Active Promoter on TiO2 Predecorated MnOx Catalysts for the NH3-SCR Reaction

MnO_x-based catalysts possess excellent low-temperature NH₃ selective catalytic reduction (NH₃-SCR) activity, but the poor SO₂/sulfate poisoning resistance and the narrow active-temperature window limit their application for NO_x removal. Herein, TiO₂ nanoparticles and sulfate were successively introduced into MnO_x-based catalysts to modulate the NH₃-SCR activity, and the active-temperature window (NO conversion above 80%, T₈₀) was significantly broadened to 100-350 °C (SO₄^2--TiO₂@MnO_x) compared to that of the pristine MnO_x catalyst (ca. T₈₀: 100-268 °C). Combined with advanced characterizations and control experiments, it was clearly shown that the poisonous effects of sulfate on the MnO_x catalyst could be efficiently inhibited in the presence of TiO₂ species due to the interaction between sulfate and TiO₂ to form a solid superacid (SO₄^2--TiO₂) species as NH₃ adsorption sites for the low-temperature process. Furthermore, such solid superacid (SO₄^2--TiO₂) species could weaken the redox ability to inhibit the excessive oxidation of NH₃ and thus enhance the high-temperature activity significantly. This work not only puts forward the TiO₂ predecoration strategy that converts sulfate to a promoter to broaden the active temperature window but also experimentally proves that the requirement of redox ability and acidity in the MnO_x-based NH₃-SCR catalyst was dependent on the reaction temperature range.

Advantageous Role of Ir0 Supported on TiO2 Nanosheets in Photocatalytic CO2 Reduction to CH4: Fast Electron Transfer and Rich Surface Hydroxyl Groups

Ir-based heterogeneous catalysts for photocatalytic CO₂ reduction have rarely been reported and are worthy of investigation. In this work, TiO₂ nanosheets with a higher specific surface area and more oxygen vacancies were employed to support Ir metal by impregnation (Imp) and ethylene glycol (EG) reduction methods. In comparison with Ir/TiO₂ (Imp) and TiO₂, Ir/TiO₂ (EG) exhibited excellent photocatalytic performance toward CO₂ reduction, especially for CH₄ production on account of the oxygen defect of TiO₂ and rich surface hydroxyl groups produced from the interaction between TiO₂ nanosheets and metallic Ir. In situ ESR suggested that the oxygen defect was significant for CO₂ adsorption/activation. Furthermore, metallic Ir was beneficial for photogenerated electron transfer, surface hydroxyl generation, and adsorption of the CO intermediate, generating more available electrons and reducing agents for CH₄ production. In situ CO₂ DRIFTS confirmed the key synergistic interaction between the oxygen defect and metallic Ir in the photoreduction from CO₂ to CH₄.

Rapid and continuous fabrication of TiO2 nanoparticles encapsulated by polyimide fine particles using a multistep flow-system and their application

PI fine particles encapsulating a large number of TiO₂ nanoparticles (PI FPs/TiO₂ NPs) were successfully fabricated rapidly and continuously by the emulsion re-precipitation method using a multistep flow synthetic system. The fabricated material, PI FPs/TiO₂ NPs, was spherical in structure with a diameter of 214 nm, and the mean size of TiO₂ NPs was 5.2 nm. Line scan elemental analysis with SEM-EDX showed that the TiO₂ NPs were disproportionately embedded near the surface of the PI FPs. UV-vis transmission spectra revealed high UV shielding efficiency of the PI FPs/TiO₂ NPs as the NPs are located near the surface.

We rapidly and continuously fabricated TiO₂ nanoparticles encapsulated by polymer fine particles, and the fabricated nanomaterials showed high UV shielding efficiency.

Application of ReOx/TiO2 catalysts with excellent SO2 tolerance for the selective catalytic reduction of NOx by NH3

The adsorption of SO₂ on ReO_x/TiO₂ catalysts was rather weak; thus, ReO_x/TiO₂ catalysts exhibited excellent SO₂ tolerance in the NH₃-SCR reaction.

A MnOx@Eu-CeOx nanorod catalyst with multiple protective effects: Strong SO2-tolerance for low temperature DeNOx processes

A novel MnO_x@Eu-CeO_x catalyst with multiple protective attributes was designed and fabricated using a chemical precipitation method and tested for its low temperature SCR activity. The subject MnO_x@Eu-CeO_x nanorod catalyst exhibited superior SCR performance and strong SO₂-tolerance. The formation of the composite-shell structure enhanced the catalysts' surface acidity and redox performance, which resulted in excellent SCR performance. Moreover, the TG results suggested that the protective effect of the EuO_x-CeO_x composite-shell effectively reduced the deposition of the surface sulphates. The XPS, XRD analysis results of the subject catalyst together with theoretical calculations provided strong evidence that there was a strong interaction between Mn and Ce in the MnO_x@Eu-CeO_x. This significant interaction could provide maximum protection to the core from the effect of SO₂, which also contributed to the high SO₂ resistance of the catalyst. In situ FT-IR results also indicated that the chemisorbed species on MnO_x@Eu-CeO_x were much more stable in the presence of SO₂ compared to Eu-CeO_x/MnO_x, which resulted in the deposition of significantly less sulphates. This low temperature SCR catalyst with multiple protective attributes, including composite shell, strong interaction and core-shell structure, is the key to long-term resistance to SO₂.

A novel regeneration method for deactivated commercial NH3-SCR catalysts with promoted low-temperature activities

A novel route is developed for regeneration of deactivated commercial NH₃-SCR catalysts, which includes an initial in situ construction of anatase TiO₂ porous film, followed by loading of MnO_x, CeO_x, and Mn-Ce mixed oxides as active components. The regenerated catalysts present largely improved low-temperature denitrification performance due to the synergetic effect of MnO_x and CeO_x. The denitrification efficiency could reach a high value of 97% at 200 °C and 100% at 250 °C when the Ce-Mn mixed oxides are loaded at the optimized molar quantity ratio of 10:9 (Ce:Mn). Properties and reaction mechanisms of the regenerated catalysts are investigated with characterizations of X-ray photoelectron spectroscopy (XPS), NH₃ temperature-programmed desorption (NH₃-TPD), H₂ temperature-programmed reduction (H₂-TPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Our results demonstrate that the adsorption and oxidation of NO plays a crucial role for these three catalysts even though a difference exists on the reaction pathways. Graphical abstract.

Performance Evaluation of a Novel Thermal Power Plant Process with Low-Temperature Selective Catalytic Reduction

We present the concept of a novel thermal power plant process in conjunction with low-temperature selective catalytic reduction (SCR). This process can be employed to achieve modern standards for NOx emissions and solve problems related to post-gas cleaning processes, such as thermal fatigue, catalyst damage, and an increase in differential pressure in the boiler. Therefore, this study is aimed at evaluating the performance of a novel flue-gas cleaning process for use in a thermal power plant, where a low-temperature SCR is implemented, along with the existing SCR. We developed a process model for a large-scale power plant, in which the thermal power plant was divided into a series of heat exchanger block models. The mass and energy balances were solved by considering the heat transfer interaction between the hot and cold sides to obtain the properties of each material flow. Using the process model, we performed a simulation of the new process. New optimal operating conditions were derived, and the effects that the new facilities have on the existing process were evaluated. The results show that the new process is feasible in terms of operating stability and cost, as well as showing an increase in the boiler thermal efficiency of up to 1.3%.

Investigating multi-functional traits of metal-substituted vanadate catalysts in expediting NOX reduction and poison degradation at low temperatures

Catalysts are severely poisoned by ammonium sulfate (AS) and ammonium bisulfate (ABS) during selective catalytic NO_X reduction (SCR) at low temperatures. To circumvent this issue, metal-substituted vanadates (MV₂O₆, M = Mn, Co, Ni, or Cu) supported on TiO₂ were synthesized and functionalized with SO_Y^2- to form M₁ (S) catalysts (Y = 3 or 4). The Mn₁ (S) could balance pre-factor and energy barrier required for the SCR, thereby exhibiting the highest NO_X consumption rate (activity) among the M₁ (S) catalysts. The Mn₁ (S) also had desirable redox property, leading to the best SCR performance maximum-obtainable at low temperatures. Notably, the Mn₁ (S) substantially reduced the thermal energy needed to decompose AS/ABS poisons. Such unique feature of the Mn₁ (S) was pronounced when the Mn₁ (S) was promoted by Sb (Mn₁-Sb (S)). The resulting Mn₁-Sb (S) showed the best SCR performance among all catalysts tested. The Mn₁-Sb (S) could minimize the deposition of AS/ABS on the surface and unprecedentedly recovered its performance after regeneration even in the presence of NO_X, NH₃, SO₂, and H₂O at 260-280 °C. The temperatures required for the regeneration of the Mn₁-Sb (S) were reduced by 100 °C or more in comparison with those of SCR catalysts reported previously.

Improved NO reduction by using metal-organic framework derived MnO x -ZnO

Derivatives based on metal frameworks (MOFs) are attracting more and more attention in various research fields. MOF-based derivatives x% MnO _x -ZnO are easily synthesized by the thermal decomposition of Mn/MOF-5 precursors. Multiple technological characterizations have been conducted to ascertain the strengthening interaction between Mn species (Mn²⁺ or Mn³⁺) and Zn²⁺ (e.g., XRD, FTIR, TG, XPS, SEM, H₂-TPR and Py-FTIR). The 5% MnO _x -ZnO exhibits the highest NO conversion of 75.5% under C₃H₆-SCR. In situ FTIR and NO-TPD analysis showed that monodentate nitrates, bidentate nitrates, bridged bidentate nitrates, nitrosyl groups and C _x H _y O _z species were formed on the surface, and further hydrocarbonates or carbonates were formed as intermediates, directly generating N₂, CO₂ and H₂O.

The enhancement of NH3-SCR performance for CeO2 catalyst by CO pretreatment

CO pretreatment was found to effectively improve the SCR performance of CeO₂, with over 90% at about 300 °C. The larger specific area and the decrease of CeO₂ crystallization indicated the modification of the surface structure after CO pretreatment. Abundant Ce³⁺ species and active oxygen, better reducibility, and the higher surface adsorption capacity were mainly responsible for its enhanced SCR performance. DRIFT analysis revealed the presumed coexistence of two reaction routes that the L-H mechanism was related to the reaction temperature, while the reaction rate of E-R route was almost directly proportional to the NO concentration at a certain temperature, based on the kinetic calculation. In addition, the CO-pretreated CeO₂ also exhibited a better poisoning tolerance for SO₂ and H₂O and excellent thermal stability and circularity. Graphical abstract The process of NH₃-SCR reaction over CeO₂-CO catalyst.

Mechanism and regeneration of sulfur-poisoned Mn-promoted calcined NiAl hydrotalcite-like compounds for C3H6-SCR of NO

The selective catalytic reduction of NO with propene (C₃H₆-SCR) in the presence of SO₂ was investigated over a series of Mn-promoted calcined NiAl hydrotalcite-like compounds. The obtained 5% MnNiAlO catalyst exhibits superior NO conversion efficiency (95%) at 240 °C, and excellent sulfur-poisoning resistance. The possible reaction pathways of the catalytic process were proposed according to several characterization measurements. It is demonstrated that Mn-promoted NiAlO catalysts enhance the Brønsted acid sites and surface active oxygen groups, and improve the redox properties by the redox cycle (Ni³⁺ + Mn²⁺ ↔ Ni²⁺ + Mn⁴⁺). Thus, the amount of the reaction intermediates is improved, and the reactivities between C_xH_yO_z species and nitrite/nitrate species are promoted. Furthermore, in the presence of SO₂, the MnNiAlO samples can give rise to minor formation of sulfate and inhibit the competitive adsorption effectively due to their nitrite/nitrate species being more abundant and stable. Finally, regeneration was studied using in situ FTIR and the water washing method showed the best performance on the regeneration of S-poisoned catalysts.

The selective catalytic reduction of NO with propene (C₃H₆-SCR) in the presence of SO₂ was investigated over a series of Mn-promoted calcined NiAl hydrotalcite-like compounds.

MnO2–GO-scroll–TiO2–ITQ2 as a low-temperature NH3-SCR catalyst with a wide SO2-tolerance temperature range

GO-scroll–TiO₂–ITQ2 improved the steam-resistance and SO₂-resistance of the low-temperature manganese-based NH₃-SCR catalyst.

Significantly enhanced Pb resistance of a Co-modified Mn–Ce–Ox/TiO2 catalyst for low-temperature NH3-SCR of NOx

Co modification can significantly improve the performance for low-temperature NH₃-SCR of NO_x and the Pb resistance of the Mn–Ce–O_x/TiO₂ catalyst.

Novel metal-organic framework supported manganese oxides for the selective catalytic reduction of NOx with NH3: Promotional role of the support

A novel MnOx@MIL-125(Ti) catalyst was constructed for the selective catalytic reduction (SCR) of NOx with NH₃, in which MIL-125(Ti), a kind of metal-organic frameworks (MOFs), was used as the support because of the structural feature, large surface area and high thermal stability. The SCR results showed that MnOx@MIL-125(Ti) exhibited high deNOx ability and N₂ selectivity in a wide operating temperature range. Moreover, it exhibited better SO₂ resistance than MnOx/TiO₂(P25). Characterization results revealed that MIL-125(Ti) had resulted in a high dispersion of MnOx and a strong metal-support interaction for MnOx@MIL-125(Ti), which could promote the formation of the abundant Mn⁴⁺ and surface chemical oxygen, facilitating the activation of the reactants. In situ DRIFTS results suggested that NH₃-SCR over MnOx@MIL-125(Ti) followed both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanism. In addition, NO^- species were proved to be the important intermediates which were involved in SCR reaction.