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Non-thermal plasma with different O 2 concentration in discharge atmosphere was applied to synthesize manganese and cerium mixed-oxides catalysts, which were compared in NO oxidation activity. Discharge atmosphere displayed a crucial influence on the performance of the catalysts prepared by plasma. Relatively low O 2 concentration in discharge atmosphere allows synthesizing manganese-cerium oxides catalysts in a moderate environment and therefore is favorable for better physicochemical properties which lead to superior catalytic behavior. The best catalyst was obtained by treatment with 10% O 2 /N 2 plasma and presented over 80% NO conversion in the temperature range of 275–325 °C, whereas catalyst prepared in pure O 2 discharge atmosphere had the same activity with a catalyst prepared by calcinations. A correlation between the surface properties of the plasma prepared catalysts and its catalytic activity in NO oxidation is proposed. The amount of the surface adsorbed oxygen has an obvious linear correlation with the amount of Ce 3+ , the H 2 consumption at low temperatures and the catalytic performance. The superior catalytic performance is mainly attributed to the stronger interaction between manganese oxides and ceria, and the formation of poorly crystallized Mn-O-Ce phase in the catalyst which resulted from the slow decomposition of nitrates and organics during plasma treatment. Catalysts prepared in relatively low O 2 concentration have large specific surface area and is abundant in Ce 3+ species and active oxygen species. The study suggests that plasma treatment with proper discharge gas components is a promising method to prepare effective manganese- cerium oxides catalyst for NO oxidation. [ABSTRACT FROM AUTHOR]

Four typical coal-fired power plants were employed to explore the performance evolution within the whole life cycle of catalysts. The results revealed that the amount of active ingredients in the catalysts decreased over time. The content of V 2 O 5 and WO 3 in four units had decreased by 3.32%–32.8% and 12.9%–22.9% respectively. However, alkali metals and alkaline earth metals in flue gas were gradually deposited on the catalyst and led to catalyst poisoning, especially in two units due to arsenic poisoning. The specific surface area of catalysts decreased significantly in the first year of operation, accounting for 87.3%, 47.8%, 55.1% and 86.7% of the decline in the lifetime, which may be the main reason for the decline of catalyst activity during this period. The wall thickness of catalysts decreased linearly with the operation time in the lifetime. The relative activity of catalysts at the end of designed service lifetime was between 0.90 and 0.93, whereas the decrease range of SO 2 /SO 3 conversion rate was within 15.4%–35.6%. Influenced by the catalyst design and the variations of practical operation conditions, the difference between the actual and designed service lifetimes of catalysts in the four units was 2.08%, 44.0%, 4.17%, and − 25.0%, respectively. • SCR catalyst of four typical coal-fired power plant was investigated. • Catalyst performance evolution in three consecutive years of operation were analyzed. • A method for checking actual service lifetime of SCR catalyst was proposed. • Difference between the actual and designed catalyst lifetimes was obtained. • K/K 0 at the end of catalyst service lifetime was between 0.91 and 0.93. [ABSTRACT FROM AUTHOR]

Recycling of valuable metals from spent catalysts in a green way is gaining extensive interest for economic and environment reasons. In this study, we developed novel hydrophobic deep eutectic solvents to extract Mo from spent catalysts. The hydrophobic DESs have been designed and synthesized by mixing one molar of the quaternary ammonium salt and two molars of various saturated fatty acids with different carbon chain lengths. The extraction ability and extraction mechanism of these DESs were studied, some factors influencing the extraction efficiency, including the structure of hydrogen bond acceptors and hydrogen bond donors, initial aqueous pH, reaction time and temperature, phase ratios were investigated. It is found that the synthesized hydrophobic DESs exhibit excellent extraction performance toward Mo, where the Mo distribution ratio is more than 2200 in the presence of other metals, corresponding to an extraction efficiency of 99% at optimal reaction conditions. This work reveals a distinct class of materials, guiding an effective and green way for spent catalyst treatment. Implications: Novel hydrophobic deep eutectic solvents have been developed to extract Mo from spent catalysts, the synthesized hydrophobic DESs possess several advantages, such as green, low price, low toxicity, and biodegradability. It exhibits excellent extraction performance under an optimized extraction condition. This work reveals a distinct class of materials, guiding a promising way for green and economical utilization of spent catalysts. [ABSTRACT FROM AUTHOR]

Disposal of spent catalyst in an economical and green way has become a great concern for industrial production. We developed a process including acid leaching, solvent extraction and stripping in order to recycle spent catalyst. In this study, we conducted selective recovery of molybdenum through focus on finding an optimized extraction and stripping process by comparing different extractants and stripping agents. To separate molybdenum from other metals efficiently and figure out the mechanism of extraction process, the five different extractants of methyl trioctyl ammonium chloride, tri-n-octylamine, tris (2-ethylhexyl) amine, bis (2-ethylhexyl) phosphate, and tributyl phosphate with different functional groups were examined; the extraction ability and extraction mechanism of these five extractants were systematically studied under the same system for the first time. It was found that more than 98% of the molybdenum could be extracted with an organic phase consisting of tri-n-octylamine or methyl trioctyl ammonium chloride under the optimal conditions. The result indicated that the tri-n-octylamine and methyl trioctyl ammonium chloride possess excellent molybdenum extraction ability, the extraction capacity of the rest extractants was in the order of bis (2-ethylhexyl) phosphate > tris (2-ethylhexyl) amine > tributyl phosphate. In the stripping process, NH4OH, NaOH, and H2SO4 were chosen as stripping agent to strip the molybdenum from the loaded tri-n-octylamine organic phase. The stripping ability of the three studied stripping agents was in the order NaOH > NH4OH > H2SO4. The Fourier transform infrared (FTIR) spectra showed that the structure of the tri-n-octylamine organic phase was stable during the extraction and stripping process. Results showed that molybdenum could be highly and efficiently recovered by optimized extraction and stripping process. Implications: A series of different extractants and stripping agent have been systematically studied in order to compare their extraction and stripping ability under the same system. Based on the obtained results, an optimized extraction and stripping process was proposed to recycle molybdenum from spent catalyst efficiently. It is possible to dispose spent catalysts in an economic and environmental way by this developed metal recovery process. [ABSTRACT FROM AUTHOR]

Investigation of the low-temperature (LT) selective catalytic reduction (SCR) of NOx has adsorbed extensive efforts, and is now a hot topic in environmental catalysis. In this work, we cautiously explore the mechanism beneath LT-SCR via a combination of chemical-trapping methods, using BaO/Al2O3 as a NOx-intermediate trap, temperature-programmed desorption (TPD) and in situ FTIR spectroscopy over a series of metal-oxide catalysts. Our results show a linear correlation between LT-SCR rates and amounts of nitrites generated from NO oxidative activation and sequentially stored on BaO/Al2O3, implying key roles of nitrites/nitrite-precursors in LT-SCR. [ABSTRACT FROM AUTHOR]

• The reaction behaviours of DCM over anatase TiO 2 -supported RuO 2 and V 2 O 5 were investigated. • The distribution of RuO 2 and acidity of the catalysts greatly influenced the product distribution. • The RuO 2 &V 2 O 5 /TiO 2 is effective for DCM catalytic decomposition. Three catalysts with RuO 2 and V 2 O 5 as the active components loaded on anatase TiO 2 were prepared and used for the catalytic decomposition of dichloromethane (DCM). The V 2 O 5 /TiO 2 showed higher CO selectivity and lower CH 3 Cl selectivity than RuO 2 /TiO 2. Further characterization of these samples demonstrated that the V 2 O 5 loading can promote the acidity of TiO 2 , which is beneficial for the adsorption of DCM and cleavage of C-Cl bonds, thus leading to a higher low temperature catalytic activity than RuO 2 /TiO 2. Meanwhile, the EDS-mapping and XRD results indicated that RuO 2 agglomerated over the surface of anatase TiO 2. Therefore, a portion of the DCM directly decomposed over the bare surface of TiO 2 and led to the production of CH 3 Cl, which is more stable than CH 2 Cl 2 and difficult to decompose. However, the loading of RuO 2 greatly enhanced the redox properties of the catalyst by enriching the surface oxygen species and promoted the deep oxidation processes to improve the selectivity of the product to CO 2. Finally, the RuO 2 &V 2 O 5 /TiO 2 catalyst was synthesized and used for the decomposition of DCM. The results demonstrated that the RuO 2 &V 2 O 5 /TiO 2 , which coupled the oxidation centre (RuO 2) with the acid centre (V 2 O 5), shows wonderful prospects for application in DCM decomposition. [ABSTRACT FROM AUTHOR]

Abstract In this study, the cobalt-cerium spinel oxides catalysts were prepared via a citric acid complex method. The catalytic performance and physicochemical properties of the samples for deep propane oxidation were evaluated. Co 2 Ce 1 O x catalysts exhibit the superior low temperature activity with a T 50 value of 220 °C, which is much lower than both individual cobalt and cerium oxides. The results show that cerium ions could enter into the spinel-type lattice of the cobalt oxides and lead to the severe lattice distortion. The activated Co O bonds favor the propane activation and enhance the reducibility of active Co3+ species. Meanwhile, high proportion of Co3+ content and better oxygen mobility are also observed in the cobalt-cerium spinel oxides catalysts. The kinetic and the transient experiments reveal that the reduction step of the catalysts plays a crucial role in the deep catalytic propane oxidation. The reaction rate of Co 2 Ce 1 O x catalyst reaches 0.22 μmol g−1 s−1 at 200 °C and its activation energy is the lowest (57.9 kJ mol−1). All the results indicate that the combination of redox behaviors of Co 3 O 4 and oxygen vacancies of CeO 2 offer useful support for catalysts design toward propane oxidation at low temperature. Graphical abstract Unlabelled Image Highlights • Catalytic propane oxidation was performed over cobalt-cerium spinel oxides catalysts. • Co 2 Ce 1 O x showed the highest low temperature activity. • Reduction step of the catalysts is crucial for catalytic propane oxidation. • Proportion of Co3+ is linear with the reaction rates at 200 °C. [ABSTRACT FROM AUTHOR]

Abstract In recent years, significant effort has been made in the development of novel catalysts for the total oxidation of chlorinated volatile organic compounds. In this work the catalytic activity of Cu doped cerium-titanium binary oxides for the oxidation of dichloromethane (DCM) have been studied for the first time. Combining catalysts characterization and activity data, it was found that Cu ions can uniformly disperse into titanium dioxide to form solid solution and induce the creation of additional surface oxygen species on the catalysts surface, while moderate amount of Ce ions are still needed for the activation of C Cl. Detailed analysis of the in-situ FTIR experiment results revealed that the surface oxygen species, especially the hydroxyl groups associated with Cu ions, can promote the deep oxidation of the intermediate species formed in the nucleophilic substitution process occurred on the active sites of catalysts surface. The sample with the Cu/Ce molar ratio of 1:3 obtained a better CO 2 selectivity than that reached with cerium-titanium binary oxides. Meanwhile, according to element balance analysis, removal of chlorine from the catalyst surface was also promoted by Cu doping. Graphical abstract Image 1 Highlights • Catalytic oxidation of dichloromethane over Ce, Cu, Ti ternary oxides has been studied. • Cu doping can promote the products selectivity to CO2 and enhance Cl balance. • Correlation between catalyst structure and catalytic behavior is revealed. • Promotion Mechanism of Cu doping for dichloromethane deep oxidation was explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel catalysts for CVOCs removal present excellent low-temperature activity and high chlorine resistance. • WO x loading affects the surface species morphology while polymer structure at 10% loading shows the best performance. • The RuO 2 -WO x /Sn 0.2 Ti 0.8 O 2 catalysts exhibit highly stable activity in both dry and wet conditions. • Experimental and computational results prove WO 2 Cl 2 to be the main species for tungsten loss on chlorine poisoned catalysts. • The removal performance of CB, TCE and DCM by the cordierite catalyst is validated. The development of catalysts with high activity, selectivity, and durability is crucial for the catalytic oxidation of chlorinated volatile organic compounds (CVOCs). Although acid-modified supports are widely used in catalysis to improve the catalytic activity at low temperature, the acid sites are easily deactivated by Cl poisoning, and the poisoning mechanism remains unclear. Here, a series of RuO 2 -WO x /Sn 0.2 Ti 0.8 O 2 catalysts were synthesized for dichloromethane (DCM) catalytic oxidation. Spectroscopic characterizations revealed that the loading amount of tungsten oxide highly affects the structure of the surface species and, consequently, the low-temperature catalytic activity. SEM, XRD and DFT calculations elucidated that the loss of tungsten species in the form of WO 2 Cl 2 is the main reason for the catalyst deactivation. By loading RuO 2 , the loss of tungsten species could be effectively avoided via the Deacon reaction. The cordierite catalyst exhibits excellent catalytic activity for the oxidation of different types of CVOCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalyst high-temperature activity was greatly enhanced through adding HSiW. • Doping HSiW led to the formation of abundant acid sites on the catalyst surfaces. • Adding HSiW lowered the amount and reactivity of catalyst surface oxygen species. • The balance of the acidity and oxidability played a key role in the SCR activity. A series of H 4 SiW 12 O 40 -modified Fe 2 O 3 catalysts were synthesized using the precipitation method. Over 80% NO x conversion was obtained in the temperature region of 250–450 °C for the catalysts with the H 4 SiW 12 O 40 content of 5% and 10%. The relationship between the physicochemical properties and performances of the series catalysts was established. Abundant acid sites were introduced with doping H 4 SiW 12 O 40 , which promoted the adsorption of reductant NH 3 on the catalysts at high-temperature regions. Moreover, adding H 4 SiW 12 O 40 lowered the amount and reducibility of catalyst surface reactive oxygen species, which inhibited the oxidation of NH 3 to NO x at higher temperatures to some extent. Thus, most ammonia species were prone to participating in the reaction with NO x instead of being directly oxidized to NO x in the higher temperature region over the H 4 SiW 12 O 40 -decorated catalysts. And it could be concluded that the balance of the acid and redox properties constituted the main reason for the superior activity of the high H 4 SiW 12 O 40 content catalysts. Additionally, SO 2 exerted a slight and reversible inhibition effect on the catalyst activity at 300 °C, suggesting that HSiW-modified Fe 2 O 3 oxide might be a promising catalyst in practical applications. [ABSTRACT FROM AUTHOR]

• Developed a molecular dynamics model to study the nano-scale transport of gaseous pollutants in titania-based catalysts. • Investigated the diffusivity under the impacts of different molecules, temperatures, pore widths and hydroxyl sites. • Studied the influences of competitive diffusion of mixed pollutant molecules on the diffusivity. Mass transfer can significantly affect the SCR process which is designed for NOx removal. However, it is still challenging to characterize the transport of gaseous species involved in the process, especially at nano-scale. This work probes into the application of non-equilibrium molecular dynamics (NEMD) simulations to study the mass transfer of multi-pollutants over a titania-based catalyst. A dual control-volume (DCV) model was proposed to simulate transport of typical gaseous molecules (e.g. NO, NH 3 and SO 2). The impacts of temperature, pore width, hydroxyl sites and competitive diffusion on diffusivity of objective molecules were studied in details. The results showed that temperature and surface sites could affect NH 3 more significantly than NO and SO 2 , yet the influence of surface sites was strongly size-dependent. The reduction in NH 3 diffusivity caused by the presence of surface sites decreased from 32.37 % to 2.97 % when the pore width grows from 25 Å to 75 Å. The competitive transport between NH 3 and SO 2 has also mitigated the impacts of surface sites on both molecules. [ABSTRACT FROM AUTHOR]

Ceria has absorbed extensive interests in functioning as catalysts for low-temperature (LT) selective catalytic reduction (SCR) of NOx due to its abundant surface oxygen species and salient redox property. The mechanistic interpretations of how such redox property contributes to its LT-SCR activity, however, still remain debated. Here, we use a model tungsten-promoted ceria catalyst (WO 3 /CeO 2), known as preeminent in LT-SCR reactions, and combine steady-state kinetic, structural characteristic and in situ spectroscopic experiments with theoretical treatments to reveal the mechanistic connections between NO oxidative activation and LT-SCR turnovers. We show that, compared with NO oxidation to NO 2 , NO oxidative activation to nitrite intermediates is both kinetically and thermodynamically more favorable; surface nitrate species are not detected in the present case, indicating their more difficult formation than nitrites. All these results thus suggest the prevalence of NO activation to nitrites over NO to nitrates or oxidation to NO 2 and subsequent occurrence of fast SCR in the WO 3 /CeO 2 -catalyzed LT-SCR reaction. These findings progress the understanding of LT-SCR reaction mechanism on CeO 2 -based catalysts and convey a detailed perspective of different reaction intermediates and their consequences for LT-SCR turnovers, which may contribute to the rational design of catalysts towards further improved LT-SCR activity. [ABSTRACT FROM AUTHOR]

In this work, plasma-catalytic removal of low concentrations of acetone over CuO/γ-Al 2 O 3 catalysts was carried out in a cylindrical dielectric barrier discharge (DBD) reactor. The combination of plasma and the CuO/γ-Al 2 O 3 catalysts significantly enhanced the removal efficiency of acetone compared to the plasma process using the pure γ-Al 2 O 3 support, with the 5.0 wt% CuO/γ-Al 2 O 3 catalyst exhibiting the best acetone removal efficiency of 67.9%. Catalyst characterization was carried out to understand the effect the catalyst properties had on the activity of the CuO/γ-Al 2 O 3 catalysts in the plasma-catalytic reaction. The results indicated that the formation of surface oxygen species on the surface of the catalysts was crucial for the oxidation of acetone in the plasma-catalytic reaction. The effects that various operating parameters (discharge power, flow rate and initial concentration of acetone) and the interactions between these parameters had on the performance of the plasma-catalytic removal of acetone over the 5.0 wt% CuO/γ-Al 2 O 3 catalyst were investigated using central composite design (CCD). The significance of the independent variables and their interactions were evaluated by means of the Analysis of Variance (ANOVA). The results showed that the gas flow rate was the most significant factor affecting the removal efficiency of acetone, whilst the initial concentration of acetone played the most important role in determining the energy efficiency of the plasma-catalytic process. [ABSTRACT FROM AUTHOR]

Arsenic (As) is found to be poisonous to the commercial V 2 O 5 WO 3 /TiO 2 catalysts for selective catalytic reduction of NO x with NH 3 . The NO x conversion of catalysts declines and N 2 O formation dominates at high temperature (above 300 °C) after As poisoning. A series of activity and characterization experiments are applied to reveal the deactivation mechanism caused by As. Results indicate that doping of As on the catalysts, which exists as H 2 AsO 4 − and HAsO 4 2− , doesn’t seriously change surface area of catalysts or TiO 2 phase, but greatly decreases both the Lewis and Brønsted acid sites. It is found that V OH is destroyed and less reactive As OH is newly formed. V OH site is crucial to the NH 3 adsorption and its destruction by As contributes to catalyst deactivation. Besides, stronger oxidizability of catalysts that resulted from more surface-active oxygen aroused by As leads to substantial non-selective catalytic reduction reaction and NH 3 oxidation at high temperature. Both of these two aspects result in lower NO x conversion and higher N 2 O formation. However, SO 4 2− can provide remarkable surface acidities and the sites that destroyed by As can thus be supplied. Benefited from these new reactive acid sites, catalysts with prominent SO 4 2− loading show superior arsenic resistance even with a high As content, which indicate to be a promising anti-poisoning formula. Finally, mechanism of arsenic poisoning and resistance effect of SO 4 2− is proposed based on the above analysis. [ABSTRACT FROM AUTHOR]

A post-plasma catalysis system has been developed for the removal of methanol over Mn–Ce oxide catalysts with different Mn/Ce molar ratios at low temperatures. The Mn 50 Ce 50 oxide catalyst (Mn/Ce = 1:1) shows the best performance in terms of methanol removal efficiency and energy efficiency of the plasma-catalytic process. The maximum methanol removal efficiency of 95.4% can be achieved at a discharge power of 15 W and a gas flow rate of 1 L/min, while the highest energy efficiency of the plasma-catalytic process is 47.5 g/kW h at 1.9 W. The combination of plasma and Mn–Ce catalysts significantly reduces the formation of major by-products (methane, formaldehyde and formic acid) based on the Fourier transform infrared spectra. Possible reaction mechanisms and pathways of the post-plasma catalytic removal of methanol are also proposed. A three-layer back propagation artificial neural network (ANN) model has been developed to get a better understanding of the roles of different process parameters on methanol removal efficiency and energy efficiency in the post-plasma catalytic process. The predicted data from the ANN model show a good agreement with the experimental results. Catalyst composition (i.e. Mn/Ce ratio) is found to be the most important factor affecting methanol removal efficiency with a relative importance of 31.53%, while the discharge power is the most influential parameter for energy efficiency with a relative weight of 30.40%. These results indicate that the well-trained ANN model provides an alternative approach for accurate and fast prediction of the plasma-catalytic chemical reactions. [ABSTRACT FROM AUTHOR]

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities. [ABSTRACT FROM AUTHOR]

• Developed a new RuO 2 -WO 3 /Sn 0.2 Ti 0.8 O 2 catalyst formula for CVOCs catalytic removal. • Studied the effect of RuO 2 loading on catalyst's acidity and catalytic performance. • Studied the synergistic catalysis of CVOCs and multiple pollutant components. Chlorine-containing volatile organic compounds emitted from combustion boilers and chemical industries will cause great harm to the ecological environment and human health. Catalytic combustion technology is one of the commonly used technologies for the treatment of CVOCs. Poor low-temperature activity, high levels of toxic by-products, and poor resistance to chlorine poisoning are common problems faced by its catalyst development. In order to effectively remove CVOCs, we constructed a RuO 2 -WO 3 / Sn 0.2 Ti 0.8 O 2 catalyst formula in which RuO 2 and WO 3 were supported on Sn 0.2 Ti 0.8 O 2 , and tested with DCM as a model molecule. By detecting the catalytic performance of RuO 2 -WO 3 /Sn 0.2 Ti 0.8 O 2 series catalysts with different RuO 2 loadings on DCM and corresponding characterization methods, we found that 3 wt%RuO 2 -5 wt%WO 3 /Sn 0.2 Ti 0.8 O 2 catalyst had the best catalytic performance (T 90% value was 291 °C, CO 2 selectivity was close to 100% at 325 °C). The actual industrial environment often contains multiple gas pollutants at the same time, so it is important to study the ability of the catalyst to co-process multiple pollutants. The effects of other pollutants (propane, acetone, SO 2 and NO 2) in the reaction atmosphere on the catalytic oxidation performance of DCM were further studied. It was found that the RuO 2 -WO 3 /Sn 0.2 Ti 0.8 O 2 catalyst could achieve the coordinated removal of acetone, propane and dichloromethane, and the effects of SO 2 and NO 2 on catalytic oxidation performance of DCM was revealed. It is hoped that it can serve as a reference and guidance for the subsequent industrial application of the catalyst in this system. [ABSTRACT FROM AUTHOR]

Considering the practical requirements for continuous operation under part load condition, the commercial honeycomb selective catalytic reduction (SCR) catalyst was modified with Sb addition. Experiments were performed to investigate the effect of modification on long-time SCR performance under part load condition. Characterizations for the original and modified catalysts were also conducted to analyze the changes of the catalysts. The results indicated that the activity of modified catalyst was obviously enhanced in the temperature range of 275–325 °C and it achieved about 64.5% removal efficiency during the 30 h stability test at 275 °C. The characterization results indicated that the ammonium sulfate was chemically adsorbed on the catalyst surface at low temperatures, which led to the decrease of the specific surface area, pore volume, and V4+/V5+ ratio of the catalysts. These are the reasons for the decrease of the catalyst activity at low temperatures, while the deposition amount of ammonium sulfate was relatively small over the modified catalyst. In addition, the decomposition temperature of the ammonium sulfate was reduced in the modified catalyst compared with the original one. NH4+ ions decomposed at 275 °C by reacting with the NOx in the flue gas, and the dynamic equilibrium of this reaction was achieved on the modified catalyst after a short period of time. Therefore the modified catalyst can be continuously and stably operated at this temperature, and the part load operation of the SCR system in the coal-fired power plant can be realized. [ABSTRACT FROM AUTHOR]