NH3-SCR Research Articles

Enhanced low-temperature NH3-SCR performance by g-C3N4 modified Ce-OMS-2 catalyst

The xCN/Ce-OMS-2 (x is the nominal weight percentages of g-C3N4, x = 5.0, 10.0, and 15.0 wt%) catalysts were prepared via an in-situ synthesis method. Physicochemical properties of the as-prepared materials were measured by means of the XRD, TEM, SEM, BET, XPS, H2-TPR, NH3-TPD, and in-situ DRIFTS techniques, and their catalytic activities for the selective catalytic reduction of NOx with NH3 (NH3-SCR) at low temperatures were evaluated. Among all the catalysts, the 10CN/Ce-OMS-2 catalyst showed the widest temperature span for NH3-SCR reaction and the best resistance to SO2 poisoning. This may result from that the modification of g-C3N4 promoted the electron transfer in catalyst, not only increased the concentration of active Mn4+ species and chemisorbed oxygen species, but also improved the surface acidity of the catalyst. In-situ DRIFTS results further showed that the modification of g-C3N4 increased the amount of acid sites and enhanced the formation of NH3 or NO intermediates (i.e., monodentate and bidentate nitrate), which enhanced the reaction activity of the catalyst.

Unraveling the synergy between MnOx and CeO2 in MnOx-CeO2 SCR catalysts based on experimental and DFT studies

MnOx-CeO2 catalysts have shown great potential as selective catalytic reduction of NOx by NH3 (NH3-SCR) at temperature below 300 °C. While the improved catalytic activity due to the synergy between MnOx and CeO2 in MnOx-CeO2 catalysts is widely acknowledged, the synergistic mechanism in NH3-SCR reaction remains elusive due to the lack of direct evidences. In this study, we report a comprehensive study of how MnOx and CeO2 interacted during NH3-SCR in two designed MnOx-CeO2 catalysts with different Ce4+ concentration through both experimental and theoretical approaches. Our results reveal that electron transfer from Mn2+ to Ce4+ induced the formation of surface oxygen vacancy on the CeO2, leading to the synergistic promotion of low-temperature catalytic performance by establishing Mn-redox and Ce-redox cycles to activate NH3 and O2, respectively. This work provides a distinct mechanism diagram of the synergy between MnOx and CeO2, which sheds light on the rational design of low-temperature NH3-SCR catalysts.

Excellent NH3-SCR activity and significant sulfur resistance over novel core–shell Cu-SSZ-13@meso-CeO2 catalyst

A core–shell Cu-SSZ-13@meso-CeO2 catalyst with both microporous and mesoporous pores was successfully synthesized using a self-assembly technique in this research. The catalyst was tested via NH3–SCR of NOx removal from diesel exhausts. The Cu-SSZ-13@meso-CeO2 catalyst was found to have significantly improved activity at high temperatures, wider temperature range, improved hydrothermal stability, and anti-sulfur performance. After the introduction of meso-CeO2, a significant synergistic effect between the Cu2+/Ce4+ ions on the core–shell layer was observed, and the amounts of Cu2+–2Z species and acidic sites increased, which may be conducive to the superior catalytic performance of Cu-SSZ-13@meso-CeO2 contrasted to Cu-SSZ-13. Subsequent to hydrothermal treatment, Cu-SSZ-13@meso-CeO2 maintains a superior CHA-type structure, additional L-acidic sites, and isolated Cu2+ ions while being protected by a meso-CeO2 shell. In addition, in the presence of SO2, the meso-CeO2 shell in Cu-SSZ-13@meso-CeO2 reacts with SO2 to produce cerium sulfate, which serves as a protective component for the copper species on Cu-SSZ-13. Moreover, the reaction mechanism studies have indicated that NO reduction primarily adheres to the E–R mechanism on Cu-SSZ-13, whereas both L–H and E–R mechanisms contribute to Cu-SSZ-13@meso-CeO2. SO2 has a less significant inhibitive effect on the adsorption of NH3 over Cu-SSZ-13@meso-CeO2 compared with that over Cu-SSZ-13. The inhibitive influence of SO2 on Cu-SSZ-13@meso-CeO2 is primarily owing to the inhibitory adsorption of NO and the reduction of the L–H reaction path, with little effect on the E–R reaction mechanism, which is significantly affected in Cu-SSZ-13. The Cu-SSZ-13@meso-CeO2 catalyst demonstrated exceptional NH3–SCR performance, a broad temperature range, and super hydrothermal stability as well as anti-sulfur performance, indicating great application prospects for NOx removal from diesel vehicle exhausts.

Cation migration in siliceous CHA probed with DFT simulation and its catalytic implication

The migration or diffusion of cations in siliceous CHA with an approximate Si/Al ratio of 11 has been investigated to explore the impact of their location on catalytic performance, using DFT simulation. The migration of protons within the CHA cage and the resulting total energy were calculated to determine the activation energy for this migration. As the distance between the Al site and the nearby framework oxygen decreased, the activation energy for site-to-site migration decreased as well. Eventually, the proton was stabilized near the Al site, where the activation energy for reverse migration reached its maximum at 1.60 eV. The migration of Na cations and Cu cations was also examined. The activation energy for Na cations was only 0.49 eV, which can be attributed to multiple coordination and explains the facile migration. On the other hand, Cu+2 migration had an activation energy of 1.56 eV, while Cu+1 migration had an activation energy of 1.06 eV. Consequently, under the given reaction conditions, the facile migration of the catalytic component Cu+1 can be expected. Thus, CHA containing Na cations exhibits improved low-temperature activity in NH3 SCR, despite the potential for thermal degradation at high temperatures.

Promoted NH3-SCR activity and hydrothermal stability of Cu-SSZ-50 catalyst synthesized by one-pot method

Nitrogen oxide (NOx) is one of the most critical contaminants in the air, and the control of NOx emission from diesel vehicles is very important. Cu-based small-pore zeolites have already been applied for NOx abatement on diesel vehicles. Among the small-pore zeolites, Cu-SSZ-50 catalysts with good NH3-SCR catalytic activity were believed to have potential for application. In this study, a one-pot synthesis method for Cu-SSZ-50 catalysts was developed for the first time, using the co-templates of Cu-TEPA and 2,6-dimethyl-N-methylpyridinium hydroxide. In this synthesis method, Cu-SSZ-50 with various Cu contents can be obtained by adjusting the amount of Cu-TEPA without the need for a further after-treatment process. The addition of Cu-TEPA affected the framework atoms and Cu species, and a lower Si/Al ratio and more SCR active Cu species were obtained. The synthesized catalyst with a Cu/Al ratio of 0.40 exhibited over 90% NOx conversion between 200 °C and 450 °C for the selective catalytic reduction of NOx with NH3 (NH3-SCR). Meanwhile, over 80% NOx conversion could be obtained from 250 °C to 450 °C after hydrothermal aging at 750 °C for 16 h. In addition, both L-H and E-R mechanisms were proven to exist for the one-pot-synthesized Cu-SSZ-50 by in situ DRIFTS experiments. The simple synthesis procedure, excellent catalytic activity and hydrothermal stability brighten the prospects for the application of Cu-SSZ-50.

Catalytic performance of Cu/Hβ catalysts for selective catalytic reduction of NO with NH3

A series of Cu(x)/Hβ catalysts were prepared by the impregnation method and the effect on the performance of the catalysts for the selective catalytic reduction of NO with NH3 (NH3-SCR) was investigated. Characterization techniques such as XRD, N2 adsorption-desorption, NH3-TPD, NO-TPD, H2-TPR, EDS and XPS were used to investigate the physical and chemical properties of the catalysts and the reason of the decrease of catalyst activity in the presence of SO2. It was shown that the catalyst Cu(3)/Hβ, the Cu loading was 3% and Cu(2)/Hβ, the Cu loading was 2%, exhibited the better catalytic activity when the initial reaction material contained no SO2 and SO2, and t95 was 169 and 225 °C, respectively. The analysis results of the catalyst before and after the reaction showed that the main reason for the decrease of catalyst activity in the presence of SO2 was that the ammonium sulfur salt which was formed by the reaction of SO2 and NH3 in the low reaction temperature covers the catalyst active center.

Unveiling the Origin of Selectivity in the Selective Catalytic Reduction of NO with NH3 over Oxide Catalysts.

The trade-off between activity and selectivity is a century-old puzzle in catalysis. In the selective catalytic reduction of NO with NH3 (NH3-SCR), various typical oxide catalysts exhibit distinct characteristics of activity and selectivity: Mn-based catalysts show outstanding low-temperature activity and poor N2 selectivity, mainly caused by N2O formation, while Fe- and V-based catalysts possess inverse characteristics. The underlying mechanism, however, has remained elusive. In this study, by combining experimental measurements and density functional theory calculations, we demonstrate that the distinct difference in the selectivity of oxide catalysts is determined by the gap in the energy barriers between N2 formation and N2O formation from the consumption of the key intermediate NH2NO. The gaps in the energy barriers follow the order of α-MnO2 < α-Fe2O3 < V2O5/TiO2, in correspondence with the order of N2 selectivity of the catalysts. This work discloses the intrinsic link between the target reaction and side reactions in the selective catalytic reduction of NO, providing fundamental insights into the origin of selectivity.

Unexpected promotional effects of HCl over CeO2-based catalysts for NOx reduction against alkali poisoning

In the flue gas of stationary NOx emission source, HCl was deemed to be one of the poisons of NOx reduction catalysts since it can react with ammonia to form NH4Cl and adhere to oxide surface, reducing the redox property and blocking the active sites of catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR). Herein, unexpected promotional effects of HCl over CeO2-based catalysts for NOx reduction against alkali poisoning have been unraveled. The modification of gaseous HCl on the surface of CeO2 constructed Cl-Ce-O-Ce-OH and Cl-Ce-O-Ce3+ sites, providing additional Brønsted and Lewis acid sites to facilitate ammonia adsorption. It is worth noting that HCl can not only directly neutralize alkali metal to reduce alkalinity, but also increase the acidity to offset the encroachment of acid sites by alkali metal poisoning. The lower NO adsorption energy and weaker oxidation property of Cl-Ce-O-Ce3+ sites also prevented the accumulation of inert nitrate on the surface of alkali metal poisoned catalyst. This work unveils multi-promotion mechanisms for the enhanced catalytic activity and anti-alkali poisoning of gaseous HCl modified cerium-based NOx reduction catalysts, providing a new thinking based on pollutant interaction for further development of highly efficient NOx reduction catalysts in multipollutant flue gas.

Reaction mechanism of selective catalytic reduction of NO with NH3 on Fe3O4 (1 1 1) surface: Experimental and DFT studies

Iron-based catalysts have vast potential for application prospect in selective catalytic reduction of NOx with NH3 (NH3-SCR). These catalysts offer excellent SCR activity at medium and high temperatures, N2 selectivity and environmental performance. Among these catalysts, Fe3O4 catalyst is highly active and significant in the denitration reaction due to the presence of both ferrous and ferric ions. This study utilized density functional theory (DFT) in combination with experimental measurements to investigate the reaction pathway of NH3-SCR on the Fe3O4(111) surface. The research found that the surface was favorable for the adsorption of NO molecules and followed the NO activation mechanism. Upon activation of NO at the Feoct site, it reacted with NH3 to form NH2NO, This compound then underwent decomposition into N2 and H2O. The presence of O2 on the catalyst facilitated the surface dehydrogenation reaction and completed the SCR cycle reaction. Based on the DFT results, the formation of NH2NO intermediate was the rate-determining step of SCR reaction. The Fe3O4(111) surface followed the L-H mechanism, which was in line with the experimental results. This study provided novel insights into the SCR reaction process and can be useful in developing new iron-based SCR catalysts.

Insight into the low-temperature DeNOx performance of copper-based oxides: Perspective from the valence state distribution

Understanding the effect of CuOx valence state specifically is significant for constructing high-performance Cu based oxide catalyst for low-temperature selective catalytic reduction of NO with NH3 (NH3-SCR). In this work, CuOx with different valence state including Cu2O, Cu2O-CuO and CuO particles are synthetized as model catalysts, which present same variation laws in catalytic performance at 180 ℃, 210 ℃ and 240 ℃. NH3-SCR catalytic performance of Cu2O-CuO heterojunction is the best, CuO exhibits good catalytic activity, while Cu2O possesses excellent N2 selectivity. Experimental results combined with density functional theory (DFT) calculations reveal that Cu2+ favor to form monodentate nitrate and possess strong ability of activation and dehydrogenation of NH3. The energy barrier for the form of NH2* is 79.5 kJ/mol, which is much lower than that for Cu+. While Cu+ is beneficial to NH3 and NOx adsorption and the form of bidentate nitrate, which have a positive impact on improving the selectivity of N2. Moreover, the collaboration of Cu2+ and Cu+ facilitates the redox capability and the form of surface adsorbed oxygen species, thus the reaction progress is further promoted. The SCR reaction catalyzed by three samples are dominated mainly by Langmuir-Hinshelwood (L-H) mechanism at 180 ℃. While at 240 ℃, the reaction over Cu2O follows Eley-Rideal (E-R) mechanism, during which the rate-limiting step is the internal hydrogen transfer procedure (NH2NO*→NHNOH*). Over CuO, the reaction follows L-H mechanism, the process of atomic isomerism (NHNOH*+ *→N2*+H2O*) is the rate-determining step. The energy barriers are 136 and 146 kJ/mol, respectively. This work may supply important theoretical support for the preparation of high-performance Cu-based oxide catalysts.

Enhanced NH3-SCR activity at low temperatures over MnOx supported on two-dimensional TiO2 derived from ZIF-8

ZIF-8 was used as a sacrificial template to synthesize porous anatase TiO2 (TiO2(Z)), consisting of agglomerated 2D flake-like particles. TiO2(Z) exhibited a high specific surface area (259 m2 g−1), in which the external surface area was significantly larger than that of the micropores because of its 2D flake-like structure. The catalytic performance of Mn/TiO2(Z) in selective catalytic reduction with NH3 (NH3-SCR) reaction was superior to that of MnOx catalysts supported on commercially available anatase TiO2 (TiO2(G); G5 and TiO2(H); Hombikat 8602). A large portion of MnOx was introduced into the micropores of Mn/TiO2(H) and Mn/TiO2(G), whereas MnOx was mainly located on the external surface of TiO2(Z) in the form of clusters. In particular, the cause of the high catalytic activity of Mn/TiO2(Z) was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy, demonstrating that bridged nitrate species formed on MnOx played an essential role in the low-temperature NH3-SCR reaction. These bridged nitrate species were likely formed over the MnOx clusters rather than the highly dispersed MnOx. Because TiO2(Z) exhibited a high external surface area, MnOx clusters were produced mainly over the external surfaces, resulting in high catalytic activity at low temperatures in the NH3-SCR reaction. In addition, it was demonstrated that high N2 selectivity of Mn/TiO2(Z) resulted from the migration of intermediate ammonium nitrate species, which was stabilized in a micropore structure.

A superior CeO2 @TiO2 catalyst with high dispersion of CeO2 for selective catalytic reduction of NOx with NH3

NOx emissions have raised many environmental problems and posed a serious threat to human health. Development of excellent catalysts for selective catalytic reduction of NOx by NH3 (NH3-SCR) is desirable. In this study, by ingeniously encapsulating Ce ions into MIL-125 channels, CeO2 @TiO2 catalysts were prepared by annealing the Ce/MIL-125 precursor. Due to the porous framework structure of the MIL-125, a large amount of Ce ions were adsorbed into the pores, thus achieving high dispersion of CeO2 in the composites. All the CeO2 @TiO2 catalysts exhibit a NO conversion of nearly 100% at 350 ℃ and a wide temperature range larger than 200 ℃. The CeO2 @TiO2 (2/3) catalyst shows high specific surface area and porous structure. Meanwhile, a large amount of Ce3+ sites, enriched surface oxygen species, outstanding adsorption of NOx species and high surface acidity for CeO2 @TiO2 (2/3) catalyst account for the excellent NH3-SCR properties with a wide temperature range (200 ℃ ∼ 450 ℃) and excellent H2O and SO2 resistance.

Modified cold-rolled sludge as catalyst for selective catalytic reduction of NOx with NH3 at low temperatures

Iron-based mixed oxides are considered commercially promising environmentally friendly catalysts for selective catalytic reduction with NH3 (NH3-SCR) for removing nitrogen oxides (NOx) because of their high catalytic activity. In this work, cold-rolled sludge with high content of iron species was used as the iron precursor for preparing catalysts by supported MnOx and/or sulfuric acid modifications. The prepared catalyst showed 100 % of NOx conversion in the temperature range of 60–180 ℃ and exhibited good resistance to SO2 and H2O. This is mainly attributed to the synergy between MnOx and iron sulfate, which improved the denitration performance at super low-temperature by improving the textural properties, redox capacity, surface acidity, and surface chemical states of the catalyst. Furthermore, the presence of Fe3+ and SO42- protected the active ingredient from the poisoning of SO2 and improved its sulfur resistance. The super low-temperature reaction mechanism of the catalyst was unraveled by transient reaction experiments and In situ DRIFTS. The results show that both Brønsted and Lewis acid sites are present in 10 %Mn/CRS-S-400, and that the reaction is dominated by the Langmuir–Hinshelwood (L–H) mechanism. This study provides an innovative and cost-effective strategy for the design of NH3-SCR catalysts by sulfation iron-based mixed oxides.

Effects of impregnation sequence on the NH3-SCR activity and hydrothermal stability of a Ce-Nb/SnO2 catalyst

Hydrothermal stability is crucial for the practical application of deNOx catalyst on diesel vehicles, for the selective catalytic reduction of NOx with NH3 (NH3-SCR). SnO2-based materials possess superior hydrothermal stability, which is attractive for the development of NH3-SCR catalyst. In this work, a series of Ce-Nb/SnO2 catalysts, with Ce and Nb loading on SnO2 support, were prepared by impregnation method. It was found that, the NH3-SCR activities and hydrothermal stabilities of the Ce-Nb/SnO2 catalysts significantly varied with the impregnation sequences, and the Ce-Nb(f)/SnO2 catalyst that firstly impregnated Nb and then impregnated Ce exhibited the best performance. The characterization results revealed that Ce-Nb(f)/SnO2 possessed appropriate acidity and redox capability. Furthermore, the strong synergistic effect between Nb and Sn species stabilized the structure and maintained the dispersion of acid sites. This study may provide a new understanding for the effect of impregnation sequence on activity and hydrothermal stability and a new environmental-friendly NH3-SCR catalyst with potential applications for NOx removal from diesel and hydrogen-fueled engines.

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.

Synergistic effect between the acidity and redox performance of the SO42−-CeO2 catalysts for NO reduction

Herein, a series of SO42−-CeO2 catalysts were synthesized by a sol-gel method for the selective catalytic reduction of NO by NH3 (NH3-SCR). The introduction of SO42− endowed composite catalyst with higher catalytic activity than pure CeO2. In particular, 3% SC with 3% SO42− showed over 90% NO removal between 247 and 450 °C. SO42− promoted the increase of Ce3+ content, adsorbed oxygen, and surface acidity of the composites. Furthermore, the interaction between SO42− and cerium oxide induced the synergistic effect between acidic sites and redox sites in the NH3-SCR reaction. The introduction of SO42− significantly supported the increase of B-acid and the enhancement of l-acid sites, and promoted the NH3-SCR reaction to follow both Eley-Rideal and Langmuir-Hinshelwood mechanisms.

The enhancement effect of Nb over CeSi2 catalyst for the low-temperature NH3-SCR performance

Tuning the acid site on the surface of the catalyst tends towards facilitating the selective reduction of NOx by NH3 (NH3-SCR). In this study, a set of catalysts for the Nb/CeSi2 with different loadings of niobium were synthesized and evaluated in terms of NH3-SCR over a broad temperature range. The results indicated that a catalyst for 20Nb/CeSi2 exhibited the best low-temperature NH3-SCR performance while maintaining excellent SO2/H2O resistance. These catalysts were also characterized by BET, XRD, Raman, NH3-TPD, and H2-TPR to further explore the correlations between catalyst structure and performance after adding niobium. For the Nb/CeSi2 catalysts, the surface structure was blocked by niobium species, resulting in varying degrees of reduction in the specific surface areas. Also, the total acidity decreased with the declines of the specific surface areas while the acidity per unit was enhanced, which facilitates the occurrence of the SCR reaction. Furthermore, in situ DRIFTS results indicated that SCR reaction could occur following the Eley-Rideal (E-R) mechanism and Langmuir-Hinshelwood (L-H) mechanism simultaneously over 20Nb/CeSi2 catalyst, which could be attributed to the interaction between niobium and ceria in favor of the activation of inert surface nitrate, considered the primary factor for the improvement of the catalyst performance at low-temperature.

Optimized local geometry and electronic structure of MoO3/CeO2 catalyst by adding copper cations for boosted nitrogen oxide reduction performance

The construction of highly active centers over the CeO2-based catalyst for the low-temperature NH3 selective catalytic reduction of nitrogen oxides (NH3–SCR) technology in non-power industry is one of the challenges in the application field. Herein, the SCR performance of MoO3/CeO2 catalyst has been remarkably enhanced by introducing Cu to induce the generation of active MoO structure. Advanced spectroscopy characterizations reveal that the adding of Cu into MoO3/CeO2 catalyst could create unsaturated sites on CeO2 for Mo anchor, and the enhanced electrons transfer from Mo to Cu would cause the formation of a new terminal MoO with highly distorted octahedral geometry, which is a new Lewis acid site for coordinated NH3 production. Meanwhile, the added Cu creates the adsorbed site for gaseous NO and the formed Mo-O-Cu pair center facilitates the transformation of ionic NO2– generated from NO adsorption to NO2, which is conducive to the fast SCR reaction process.

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 NOx emission from vehicle exhaust. Herein, a series of sulfated modified iron-cerium composite oxide Fe1-xCexOδ-S catalysts were synthesized. Among them, the Fe0.79Ce0.21Oδ-S catalyst achieved the highest NOx 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 NOx 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 Fe0.79Ce0.21Oδ-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 NOx species and the activation of NH3 species on the catalyst surface, thus leading to the superior low-temperature activity of the catalyst.

Effect of Metal Complexing on Mn–Fe/TS-1 Catalysts for Selective Catalytic Reduction of NO with NH3

TS-1 zeolite with desirable pore structure, an abundance of acidic sites, and good thermal stability promising as a support for the selective catalytic reduction of NO with NH3 (NH3-SCR). Herein, a series of Mn-Fe/TS-1 catalysts have been synthesized, adopting tetraethylenepentamine (TEPA) as a metal complexing agent using the one-pot hydrothermal method. The introduced TEPA can not only increase the loading of active components but also prompts the formation of a hierarchical structure through decreasing the size of TS-1 nanocrystals to produce intercrystalline mesopores during the hydrothermal crystallization process. The optimized Mn-Fe/TS-1(R-2) catalyst shows remarkable NH3-SCR performance. Moreover, it exhibits excellent resistance to H2O and SO2 at low temperatures. The characterization results indicate that Mn-Fe/TS-1(R-2) possesses abundant surface Mn4+ and Fe2+ and chemisorbed oxygen, strong reducibility, and a high Brønsted acid amount. For comparison, Mn-Fe/TiO2 displays a narrower active temperature window due to its poor thermostability.