Low-temperature Activity Research Articles

Significantly enhanced low-temperature activity and SO2/H2O tolerance of Mn–Ce-Ox/TiO2 catalyst prepared by a facile citric acid assisted impregnation method

Two different Mn–Ce-Ox/TiO2 catalysts were prepared by ordinary impregnation (denoted as MCT) and citric acid assisted impregnation (denoted as MCT-CA) methods, respectively. Excellent NOx removal is achieved over MCT-CA for selective catalytic reduction with NH3 (NH3-SCR), and 100% NOx conversion is obtained at 125 °C under weight hour space velocity (WHSV) of 80000 mL/(gcat·h). Particularly, 100% NOx is converted on MCT-CA in the presence of 10 vol% H2O at 175 °C. As H2O and SO2 coexist in the reaction system for 9 h, NOx conversion can still be maintained >90%, much higher than that (22%) of MCT. A series of characterization results indicates that MCT-CA exhibits a larger BET specific surface area, pore volume, and pore size, which enhances the dispersion of Mn and Ce oxides and promotes the rapid adsorption of reactants and desorption of products. Additionally, MCT-CA possesses more Mn4+, Ce3+, chemisorbed oxygen species, and stronger reducibility, facilitating the conversion of NO to NO2. Specially, the amount of active NH3 species and active nitrate species on MCT-CA is much more than that over MCT. The combined effect of the aforementioned factors devotes to the excellent low-temperature SCR performance and tolerance to H2O/SO2 over MCT-CA.

Enhancing low-temperature CO removal in complex flue gases: A study on La and Cu doped Co3O4 catalysts under real-world combustion environment

Designing CO oxidation catalysts for complex flue gases conditions is particularly challenging in fire scenarios. Traditional flue gas simulations use a few representative gases but often fail to adequately evaluate catalyst performance in real-world combustion conditions. In this study, we developed doping strategies using La and Cu to enhance the water resistance of Co3O4 catalysts. Catalyst 0.1La-Co3O4-CuO/CeO2 exhibits exceptional low-temperature catalytic activity, achieving 100% conversion at 130 °C. This enhancement is largely due to the introduction of La, which increases the active Co3+/Co2+ ratio and suppresses hydroxyl group formation on the Co3O4 surface. Cu doping also changes the Co3O4 lattice structure, forming Cu+ as active sites and enhancing the activity at low temperatures. For the first time, steady-state tube furnace and fixed bed were employed to evaluate the catalytic performance of CO in actual combustion atmosphere. Catalyst 0.1La-Co3O4-CuO/CeO2 maintains excellent catalytic efficiency (T100 = 120 °C) under well-ventilated conditions. However, its activity significantly decreases in poorly ventilated environments, due to the competitive adsorption of small molecules at active sites, such as acetone, commonly found in smoke. This study provides valuable insights for designing water-resistant, low-temperature, non-noble metal catalysts and offers a methodology for evaluating CO catalytic activity in real-world environments.

Specific roles of lattice oxygen and asymmetric interface Cu-[Ox]-Ce structure-relating chemisorbed oxygen over CuO/CeO2 on the catalysis of benzene combustion

Copper-ceria catalysts exhibit high prospects in the catalysis of VOCs combustion, during which lattice oxygen and chemisorbed oxygen species play indispensable roles. However, understanding their specific operating mechanisms still remains a challenge. Shaped CeO2 and CuO/CeO2 counterparts were synthesized for benzene catalytic combustion. Pure CeO2, especially for nanorod-CeO2, possessed high low-temperature activity (LTA) due to numerous active lattice oxygen following the initial step of Mars-van Krevelen mechanism. Conversely, the impaired LTA (15–40 °C upshift at 15 % conversion) but improved high-temperature activity (HTA) were obtained by varying surface local environment upon CuO loading. 5 wt% CuO/nanoparticle-CeO2 exhibited the highest mobile chemisorbed oxygen relating to the strong oxygen transfer capacity of asymmetric interface Cu-[Ox]-Ce structures affected by ceria crystal planes and sizes was verified by density functional theory calculations and experiments, despite the strong CuO-CeO2 synergistic effects. This study provides a promising direction for engineering benzene degradation catalysts with excellent low-temperature performance.

Experimental and mechanistic studies on the thermo-electric synergistic catalytic oxidation of acetone over MnO2/TiO2-Ni foam catalyst

Volatile organic compounds (VOCs) cause serious environmental and human health risks and must be efficiently removed. In this work, a metal-structured catalyst of Ni foam loaded Mn/Ti oxides was used for the oxidation of acetone, a typical VOC compound. The catalyst was in-situ joule heated when applying an electric current and produced the thermo-electric synergistic oxidation (TEO) effect. Compared with conventional thermal oxidation (CTO), the oxidation rate of acetone significantly increased by 124.19 % and the energy consumption of per unit complete oxidation rate was reduced by 66.67 % in TEO reaction with a 12 A electric current at 200 °C. The efficiency gradually improved (from 16.12 % to 36.14 %) and the energy consumption of per unit complete oxidation rate decreased (from 2.85 W/% to 0.95 W/%) with the increase of electric current. Besides, the thermal (including the catalyst thermal effect and reaction gas thermal effect) and electric effects in TEO reaction were analyzed by the statistical analysis method. With the temperature increasing from 200 °C to 400 °C, the proportion of electric effect slightly decreased while that of reaction gas thermal effect increased from 5.2 % to 18.1 %. It proved that the TEO method has the advantage of improving low-temperature catalytic activity. Furthermore, the mechanism of electric effect was investigated, in which it enhances the conversion of lattice oxygen in TiO2 to surface-adsorbed oxygen species and promotes the oxidation of Mn oxides, sequentially improving the oxidation of acetone.

Construction of multi-porous Ni-based monolithic catalyst by combining wood carbon and SBA-15 for strengthening CO2 methanation

Monolithic catalysts meet the needs of practical application compared with powder catalysts. In this work, we constructed a Ni-based monolithic catalyst (Ni/SAB-15/WWC) by in situ growth of rod-like mesoporous SBA-15 in the microchannels of wood carbon. The small Ni-based nanoparticles (∼5.3 nm) were uniformly dispersed into the mesoporous channels via a post-loading method. The monolithic Ni/SAB-15/WWC catalyst with a multilevel porous structure could provide a laminar gas flow on the surface of Ni active sites, increasing the low-temperature activity and high-temperature durability of CO2 methanation. The Ni/SAB-15/WWC with low Ni loading (∼2%) displayed superior CO2 methanation catalytic performance in terms of low-temperature activity and CH4 selectivity compared with the powder Ni/SAB-15 with high Ni loading (∼15 %). The combination of wood carbon and mesoporous materials is an innovative strategy for the design monolithic catalysts with low metal loading and excellent catalytic performance.

Enhancement of low-temperature activity of γ-Fe2O3-modified V2O5-MoO3/TiO2 catalysts for selective catalytic reduction of NOx with NH3

In this study, a series of γ-Fe2O3-modified V2O5-MoO3/TiO2 (VMT) catalysts was prepared by wet impregnation method. The γ-Fe2O3-modified catalysts exhibited excellent catalytic performance, and 1.25 wt% γ-Fe2O3 content improved the deNOx efficiency at 150 °C from 54% (unmodified VMT catalyst) to 84% (modified catalyst). BET, XRD, XPS, NH3-TPD, H2-TPR, and in situ DRIFTs were employed to characterize the physicochemical properties and reaction mechanisms of the catalysts. The introduction of γ-Fe2O3 increased the V5+/V4+ ratio, surface chemisorbed oxygen content, redox ability, and a number of acid sites in the prepared catalysts. XPS confirmed the addition of γ-Fe2O3 introduced new charge transfer pathways (Fe3+/Fe2+ ↔ V5+/V4+). In situ DRIFTs suggested that the addition of γ-Fe2O3 to the catalyst significantly increased the adsorption capacity of catalyst for NH3 and NOx, while also exerting a strong activating effect on the adsorbed NH3. Furthermore, selective catalytic reduction over the VMT and 5PEG@1.25Fe-VMT catalysts followed the Eley-Rideal (E-R) mechanism. At temperatures above 200 °C, the 5PEG@1.25Fe-VMT catalyst also followed the Langmuir-Hinshelwood (L-H) mechanism.

Unlocking the Potential of Metal-Doping Fe2O3/Rice Husk Ash Catalysts for Low-Temperature CO-SCR Enhancement.

Transition metal oxides are efficient bifunctional catalysts for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) using CO. Nonetheless, their poor activity at lower temperatures constrains broader industrial application. Herein, we propose an optimized Fe2O3-based catalyst through strategic metal doping with Cu, Co, or Ce, which engenders a harmonious balance for the synergistic removal of CO and NOx. Among the developed catalysts, Co-doped Fe2O3, supported by rice husk ash, demonstrates superior low-temperature CO-SCR activity, achieving CO and NOx conversion ratios and N2 selectivity above 98.5% at 100-500 °C. The enhanced catalytic performance is attributed to the catalyst's improved redox properties and acidity, engendered by strong Fe-Ox-Co interactions. Furthermore, the CO-SCR reaction adheres to the Langmuir-Hinshelwood and Eley-Rideal mechanisms. Our findings shed light on the future industrial application of low-temperature CO and NOx near-zero emission technology and provide a strategy for the design of low-cost SCR catalysts.

Promotion of Low-Temperature Catalytic Activity of Ru-Based Catalysts for Ammonia Decomposition via Lanthanum and Cesium Codoping

Promotion of Low-Temperature Catalytic Activity of Ru-Based Catalysts for Ammonia Decomposition via Lanthanum and Cesium Codoping

A Green Route for Sustainable Nanoporous Solid Acid Catalyst Synthesis Using Bio Template and Analysis of Its Progressive Transformation of CO2

Green chemistry approach is a most important area in the modern chemical world. The nano (meso) porous materials have the specific application in separation, adsorption and catalysis. A green template (Egg white) is used as a bio template for the synthesis of nanoporous material to replace the hazardous templates. It is a bio-degradable template; it does not create any environmental issues. The synthesized material is characterized by various spectroscopic techniques to confirm its structural formation. Based on pore size, the catalyst named as AlSiO4-14. The synthesized catalyst (AlSiO4-14) is active at 175oC. This low temperature activity will not produce coke formation at the same time it does not require any regeneration and the catalyst is continuously active for catalytic reactions. The catalytic activity of carbon dioxide decomposition is achieved at lower temperature. The complete carbon dioxide decomposition of AlSiO4-14 is 43 % is a great impact of the material.

Rational design on hierarchically porous Cu/ZSM-5 zeolite for promoting low-temperature NH3-SCR performance based on protectively alkali-etching strategy

In this study, organic structure-directing agents (OSDA) of TPA+ are used as templating agents to synthesize zeolites with different topologies, and are also served as protectants for alkali treatment to inhibit the severe silicon extraction from zeolite skeleton. The TPA+ cations could be bound to the negatively charged Al sites in the framework, so we prepared a series of Cu-based ZSM-5 catalysts with mesoporous/microporous composite structure by using TPA+ cation as a protectant for alkali treatment and evaluated the pore structures by using the hierarchy factor (HF). The results show the hierarchically mesoporous/microporous structure of the alkali-etched catalyst with the maximal HF (0.115) effectively improved the low-temperature activity on selective catalytic reduction (SCR) of NO by ammonia, achieving a complete NOx to N2 conversion at 225–400 ºC. It was shown that the TPA+ cation played an important role on protecting the crystallinity, long-range order, and pore connectivity of zeolites, and substantially widened the mesopore volume with the loss of a small portion of micropores. In addition, the alkali treatment strategy involving protectant was systematically studied, including the corresponding effect on the pore structure, redox ability, acidity, and copper ion dispersion. The N2 adsorption-desorption experiments revealed that the maximization of the HF can be obtained by adjusting the ratio of protectant to etchant (TPA+/OH-). Among them, the Cu/ZSM-5 catalyst associated with the ratio of TPA+/OH-=0.4 and the best activity has a maximum surface area of 515 m2/g, which enhances the mesopore volume (0.325 cm3/g) by approximately three times simultaneously with only a 16.9% loss of the micropore volume (0.154 cm3/g). The hierarchically porous zeolites not only enhance the diffusion of mobile hydrated copper ions and ammonia-solvated copper complexes, but also facilitate the dispersion of copper ions. This work provides a feasible strategy to rapidly enhance the low-temperature deNOx efficiency on the zeolite catalysts.

Ce enhanced RuNi alloy multi-metal synergic hydrotalcite oxide derived catalyst for high performance CO2 methanation

Ni-based methanation catalysts have problems such as low temperature activity and easy sintering. The high cost of supported Ru-based methanation catalysts limits their application in industrialization. In this work, a hydrotalcite precursor Ru-Ni-Ce-Y catalyst was prepared by co-precipitation method, and the hydrotalcite oxide catalyst was prepared by high temperature calcination. The hydrotalcite oxide catalyst was prepared by optimizing the ratio of Ni element and the amount of precious metal and rare earth metal. Compared with the traditional supported catalyst, the activity of Ru1Ni80Ce4Y20 was significantly improved. It is confirmed from the experimental results that the medium basic sites, oxygen vacancies and the synergistic effect between RuNi alloy and Ce are the reasons for the high performance of Ru1Ni80Ce4Y20. It provides a thought for the design of highly active, stable and low cost methanation catalysts in industrial methanation production.

Combined Experimental and Density Functional Theory Study on the Mechanism of the Selective Catalytic Reduction of NO with NH3 over Metal-Free Carbon-Based Catalysts.

Metal-free carbon-based catalysts are attracting much attention in the low-temperature selective catalytic reduction of NOx with NH3 (NH3-SCR). However, the mechanism of the NH3-SCR reaction on carbon-based catalysts is still controversial, which severely limits the development of carbon-based SCR catalysts. Herein, we successfully reconstructed carbon-based catalysts through oxidation treatment with nitric acid, thereby enhancing their low-temperature activity in NH3-SCR. Combining experimental results and density functional theory (DFT) calculations, we proposed a previously unreported NH3-SCR reaction mechanism over carbon-based catalysts. We demonstrated that C-OH and C-O-C groups not only effectively activate NH3 but also remarkedly promote the decomposition of intermediate NH2NO. This study enhances the understanding of the NH3-SCR mechanism on carbon-based catalysts and paves the way to develop low-temperature metal-free SCR catalysts.

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NOx with NH3.

Cu-SSZ-13 has been commercialized for selective catalytic reduction with ammonia (NH3-SCR) to remove NOx from diesel exhaust. As its synthesis usually requires toxic and costly organic templates, the discovery of alternative Cu-based zeolite catalysts with organotemplate-free synthesis and comparable or even superior NH3-SCR activity to that of Cu-SSZ-13 is of great academic and industrial significance. Herein, we demonstrated that Cu-T with an intergrowth structure of offretite (OFF) and erionite (ERI) synthesized by an organotemplate-free method showed better catalytic performance than Cu-ERI and Cu-OFF as well as Cu-SSZ-13. Structure characterizations and density functional theory calculations indicated that the intergrowth structure promoted more isolated Cu2+ located at the 6MR of the intergrowth interface, resulting in a better hydrothermal stability of Cu-T than Cu-ERI and Cu-OFF. Strikingly, the low-temperature activity of Cu-T significantly increased after hydrothermal aging, while that of Cu-ERI and Cu-OFF substantially decreased. Based on in situ diffuse reflectance infrared Fourier transform spectra analysis and density functional theory calculations, the reason can be attributed to the fact that NH4NO3 formed on the CuxOy species within ERI polymorph of Cu-T underwent a fast SCR reaction pathway with the assistance of Brønsted acid sites at the intergrowth interfaces under standard SCR reaction conditions. Significantly, Cu-T exhibited a wider temperature window at a catalytic activity of over 90% than Cu-SSZ-13 (175-550 vs 175-500 °C for fresh and 225-500 vs 250-400 °C for hydrothermal treatment). This work provides a new direction for the design of high-performance NH3-SCR catalysts in terms of the interplay of the intergrowth structure of zeolites.

Enhanced low-temperature CO2 methanation over La-promoted NiMgAl LDH derived catalyst: Fine-tuning La loading for an optimal performance

LDH-derived Ni-based catalysts are gathering momentum due to their excellent thermal stability but their low-temperature CO2 methanation is limited. In this study, various concentrations of La were introduced into the LDH-derived Ni-based catalysts for CO2 methanation, and the underlying mechanisms were investigated. The optimal Ni/La0.2-MgAlOx catalyst presented a CO2 conversion level of 69.0 % at 225 °C, which is over 7 times higher than that of conventional Ni/MgAlOx. The addition of small amounts of La could significantly enhance H spillover to promote the reduction of Ni species, but the oxygen vacancy concentration became the dominant factor causing changes in low-temperature activity as the La contents continue to increase. CO2 was found to be adsorbed at the oxygen vacancies in the form of bidentate carbonates, which are more reactive under an enhanced electron-rich environment. The research offers guidance to design effective and sustainable catalysts for low-temperature CO2 methanation.

Relationship between low-temperature oxidation activity and second-stage ignition delay: Experimental insights on n-pentanol / hydrogenated catalytic biodiesel blends

N-pentanol exhibits promising potential as a sustainable and eco-friendly biomass energy source. However, certain challenges such as ignition difficulty and unstable combustion exist. This study investigates the influence of low-temperature auto-ignition of n-pentanol/HCB (Hydrogenated Catalytic Biodiesel) blends on ignition and combustion characteristics and evaluates the correlation between low-temperature oxidation and second-stage ignition delay. Results show a linear positive correlation between the HCB content in n-pentanol and its low-temperature oxidation reactivity. The stronger the low-temperature oxidation activity of the blends, the shorter the second-stage ignition delay of blends. When the HCB content in blends is below 40 %, the low-temperature oxidation rate initially increases and then decreases. However, the low-temperature oxidation rate increases again when the HCB content exceeds 40 %. Moreover, the relationship between the initial CO2 generation rate and the HCB blending ratio follows an Exp exponential function under different critical compression ratios. Beyond 43.7 % HCB, an acceleration in the high-temperature combustion rate owing to an increase in the low-temperature oxidation rate again. In addition, the minimum ignition limit of n-pentanol/HCB blends was identified with 40 % HCB blends closely resembling diesel conditions and 50 % HCB blends showing a lower ignition limit, characterized by a critical temperature and pressure of 517.3 K and 8.66 bar, respectively. Furthermore, two distinct conditions for the minimum ignition boundary region of n-pentanol/HCB blends were defined, offering practical insights. In summary, a blend with a 50 % HCB ratio provides a promising solution for the low-temperature ignition and stable combustion of n-pentanol, addressing the challenges of simultaneous use in internal combustion engines.

FeOx-Modified Ultrafine Platinum Particles Supported on MgFe2O4 with High Catalytic Activity and Promising Stability toward Low-Temperature Oxidation of CO.

Catalytic oxidation is widely recognized as a highly effective approach for eliminating highly toxic CO. The current challenge lies in designing catalysts that possess exceptional low-temperature activity and stability. In this work, we have prepared ultrafine platinum particles of ~1 nm diameter dispersed on a MgFe2O4 support and found that the addition of 3 wt.% FeOx into the 3Pt/MgFe2O4 significantly improves its activity and stability. At an ultra-low temperature of 30 °C, the CO can be totally converted to CO2 over 3FeOx-3Pt/MgFe2O4. High and stable performances of CO-catalytic oxidation can be obtained at 60 °C on 3FeOx-3Pt/MgFe2O4 over 35 min on-stream at WHSV = 30,000 mL/(g·h). Based on a series of characterizations including BET, XRD, ICP, STEM, H2-TPR, XPS, CO-DRIFT, O2-TPD and CO-TPD, it was disclosed that the relatively high activity and stability of 3FeOx-3Pt/MgFe2O4 is due to the fact that the addition of FeOx could facilitate the antioxidant capacity of Pt and oxygen mobility and increase the proportion of adsorbed oxygen species and the amounts of adsorbed CO. These results are helpful in designing Pt-based catalysts exhibiting higher activity and stability at low temperatures for the catalytic oxidation of CO.

Hydrothermal Aging Enhances Nitrogen Oxide Reduction over Iron-Exchanged Zeolites at 150 °C.

Ammonia selective catalytic reduction (NH3-SCR) over copper- and iron-exchanged zeolites is a state-of-the-art technology for removal of nitrogen oxides (NOx, NO, and NO2) from exhaust emissions but suffers from poor low-temperature (i.e., 150 °C) activity. Here we show that hydrothermal aging of Fe-beta, Fe-ZSM-5, and Fe-ferrierite at 650 °C or higher leads to a remarkable increase in NOx conversion from ∼30 to ∼80% under fast NH3-SCR conditions at 150 °C. The practical relevance of this finding becomes more evident as an aged Fe-beta/fresh Cu-SSZ-13 composite catalyst exhibits ∼90% conversion. We propose that a neutral heteronuclear bis-μ-oxo ironaluminum dimer might be created within iron zeolites during hydrothermal aging and catalyze ammonium nitrate reduction by NO at 150 °C. Density functional theory calculations reveal that the activation free energy (125 versus 147 kJ mol-1) for the reaction of NO with adsorbed NO3- species, the rate-determining step of ammonium nitrate reduction, is considerably lower on the bis-μ-oxo ironaluminum site than on the well-known mononuclear iron-oxo cation site, thus greatly enhancing the overall SCR activity.

A Ce/hopcalite catalyst for low-temperature oxidation of CO:Preparation, performance and mechanism

The utilization of atomic-scale doping in catalysts has been recognized as an effective strategy for enhancing CO oxidation catalytic activity. This work adjusted the lattice structure of hopcalite (CuMnOx) catalysts via Ce-doping. Ce species was uniformly dispersed on the surface of amorphous porous catalysts, which built abundant interfaces along with many active sites. The lattice distortion degree can be regulated by changing Ce dosage. The modified catalysts with 7.5 wt%Ce-doping exhibited the optimal intrinsic activity for CO oxidation. Compared with the original sample, the CO conversion increased by 50 % at room temperature, and the reaction rate was eight-fold faster, superior to most reported hopcalite catalysts. Integrating with the various characterizations, the enhancing of low-temperature activity mainly originates from the weakened binding of oxygen atoms by lattice distortions. Moreover, the experiments and characterization results revealed that the reactivity of both adsorbed and lattice oxygen is enhanced on Ce-modified samples at low temperature. This work provides new insights into the rational modulation of reactive oxygen species and reinforces the utility of hopcalite catalysts for oxidizing CO at low temperature.

Heteroatoms doped iron oxide-based catalyst prepared from zinc slag for efficient selective catalytic reduction of NOx with NH3

Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment, and the development of deNOx catalysts with low-cost and high performance is an urgent requirement. Iron oxide-based material has been explored for promising deNOx catalysts. However, the unsatisfactory low-temperature activity limits their practical applications. In this study, a series of excellent low-temperature denitrification catalysts (Ha-FeOx/yZS) were prepared by acid treatment of zinc slag, and the mass ratios of Fe to impure ions was regulated by adjusting the acid concentrations. Ha-FeOx/yZS showed high denitrification performance (> 90%) in the range of 180–300 °C, and the optimal NO conversion and N2 selectivity were higher than 95% at 250 °C. Among them, the Ha-FeOx/2ZS synthesized with 2 mol/L HNO3 exhibited the widest temperature window (175–350 °C). The excellent denitrification performance of Ha-FeOx/yZS was mainly attributed to the strong interaction between Fe and impurity ions to inhibit the growth of crystals, making Ha-FeOx/yZS with amorphous structure, nice fine particles, large specific surface area, more surface acid sites and high chemisorbed oxygen. The in-situ DRIFT experiments confirmed that the SCR reaction on the Ha-FeOx/yZS followed both Langmuir-Hinshelwood (L-H) mechanism and Eley-Rideal (E-R) mechanism. The present work proposed a high value-added method for the preparation of cost-effective catalysts from zinc slag, which showed a promising application prospect in NOx removal by selective catalytic reduction with ammonia.

Improvement of Ce[sbnd]Nb doping on low-temperature catalytic activity of a VOx-based catalyst for NH3–SCR reaction

A series of VxCeNbTi catalysts were prepared using a wet impregnation method for selective catalytic reduction (SCR) of NO by NH3. The influence of CeNb addition to VTi was investigated in terms of active sites and acidity. The correlation between surface properties, catalyst structure, and performance with the addition of Ce and/or Nb was demonstrated. The composition of VCeNbTi species, surface acid properties, and redox behavior were studied. Results showed that the addition of 2CeNb to VTi increased NH3 adsorption, and brought about positive changes in Brönsted acid sites and composition of surface species. Nbn+ mainly existed as typical Nb2O5 species, forming abundant acid sites and defects on the catalyst surface, closely related to the distribution of VOx species which varied with ceria content. The presence of 2CeNb induced electron redistribution, promoting oxygen defects and reactive oxygen species formation due to the occupancy of high Vn+ (n = 4, 3). The increased proportion of Vn+ (n = 4, 3) improved catalytic activity by generating active groups on the catalyst surface. The introduction of 2CeNb enhanced SCR performance with increased NO2 generation. V2CeNbTi exhibited improved resistance in the presence of SO2/H2O, crucial for high-performance and durable catalysis.