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1.
尖晶石型复合氧化物因具有独特的结构特征而成为相对理想的柴油车尾气处理催化剂。采用溶胶-凝胶法制备尖晶石型Mn_(1-x)M_xCo_2O_4催化剂,通过X射线衍射(XRD)和程序升温氧化(TDO)等对Mn_(1-x)M_xCo_2O_4催化剂进行表征。结果表明,制备的样品Mn_(1-x)M_xCo_2O_4均为尖晶石型复合氧化物;掺杂Cu、Ce后,催化剂的氧化性能有不同程度的变化。在固定床微型反应器上对催化剂催化活性进行评价,结果表明,与纯MnCo_2O_4相比,Mn_(0.9)Ce_(0.1)Co_2O_4催化剂催化活性提高,Mn_(0.9)Cu_(0.1)Co_2O_4催化剂催化活性降低,但CO_2选择性增加。 相似文献
2.
Various spinel-type catalysts AB 2O 4 (where A = Mg, Ca, Mn, Co, Ni, Cu, Cr, Fe, Zn and B = Cr, Fe, Co) were prepared and characterized by XRD, BET, TEM and FESEM-EDS. The performance of these catalysts towards the decomposition of N 2O to N 2 and O 2 was evaluated in a temperature programmed reaction (TPR) apparatus in the absence and the presence of oxygen. Spinel-type oxides containing Co at the B site were found to provide the best activity. The half conversion temperature of nitrous oxide over the MgCo 2O 4 catalyst was 440 °C and 470 °C in the absence and presence of oxygen, respectively (GHSV = 80,000 h −1). On the grounds of temperature programmed oxygen desorption (TPD) analyses as well as of reactive runs, the prevalent activity of the MgCo2O4 catalyst could be explained by its higher concentration of suprafacial, weakly chemisorbed oxygen species, whose related vacancies contribute actively to nitrous oxide catalytic decomposition. This indicates the way for the development of new, more active catalysts, possibly capable of delivering at low temperatures amounts of these oxygen species even higher than those characteristic of MgCo2O4. 相似文献
3.
The catalytic oxidation of sulfur dioxide to sulfur trioxide over several binary (M xO y/TiO 2) and ternary (V 2O 5/M XO Y/TiO 2) supported metal oxide catalysts was systematically investigated. The supported metal oxide components were essentially 100% dispersed as surface metal oxide species, as confirmed by Raman spectroscopy characterization. The sulfur dioxide oxidation turnover frequencies of the binary catalysts were all within an order of magnitude (V 2O 5/TiO 2>Fe 2O 3/TiO 2>Re 2O 7/TiO 2 CrO 3/TiO 2 Nb 2O 5/TiO 2>MoO 3/TiO 2 WO 3/TiO 2). An exception was the K 2O/TiO 2 catalysts, which is essentially inactive for sulfur dioxide oxidation. With the exception of K 2O, all of the surface metal oxide species present in the ternary catalysts (i.e., oxides of V, Fe, Re, Cr, Nb, Mo and W) can undergo redox cycles and oxidize SO 2 to SO 3. The turnover frequency for sulfur dioxide oxidation over all of these catalysts is approximately the same at both low and high surface coverages. This indicates that the mechanism of sulfur dioxide oxidation is not sensitive to the coordination of the surface metal oxide species. A comparison of the activities of the ternary catalysts with the corresponding binary catalysts suggests that the surface vanadium oxide and the additive surface metal oxide redox sites act independently without synergistic interactions. The V 2O 5/K 2O/TiO 2 catalyst showed a dramatic reduction in the catalytic activity in comparison to the unpromoted V 2O 5/TiO 2 catalyst. The ability of K 2O to significantly retard the redox potential of the surface vanadia species is primarily responsible for the lower catalytic activity of the ternary catalytic system. The fundamental insights generated from this research can potentially assist in the molecular design of the air pollution control catalysts: (1) the development of catalysts for low temperature oxidation of SO 2 to SO 3 during sulfuric acid manufacture (2) the design of efficient SCR DeNO x catalysts with minimal SO 2 oxidation activity and (3) improvements in additives for the simultaneous oxidation/sorption of sulfur oxides in petroleum refinery operations. 相似文献
4.
Vanadium oxides supported on γ-Al 2O 3, SiO 2, TiO 2, and ZrO 2 were studied on their molecular structures and reactive performances for soot combustion. To investigate the effect of different alkali metals on the structures and reactivities of supported-vanadium oxide catalysts, they were doped into the V 4/TiO 2 catalyst which had the best intrinsic activity for soot combustion in the selected supported vanadium oxide catalysts. The experimental results demonstrated that the catalytic properties of these catalysts depended on the vanadium loading amount, support nature, and the presence or the absence of alkali metals. The spectroscopic analysis (FT-IR and UV–vis) and H 2-TPR results revealed that the higher activity of alkali-promoted vanadium oxide catalysts could be related to the ability of alkali metal promoting the redox cycle of the active vanadyl species. TG results showed that adding alkali to V m/TiO 2 catalyst was beneficial to lowering their melting points. Low melting points could ensure the good surface atom migration ability, which would improve the contact between the catalyst and soot. Due to the alkali metal components promoting the redox ability and the mobility of the catalysts, alkali-modified vanadium oxide catalysts could remarkably improve their catalytic activities for soot combustion. The catalytic activity order for soot combustion followed Li > Na > K > Rb > Cs in the catalyst system of alkali-V 4/TiO 2, and the reason why it followed this sequence was discussed. 相似文献
5.
The influence of catalyst pre-treatment temperature (650 and 750 °C) and oxygen concentration ( λ = 8 and 1) on the light-off temperature of methane combustion has been investigated over two composite oxides, Co 3O 4/CeO 2 and Co 3O 4/CeO 2–ZrO 2 containing 30 wt.% of Co 3O 4. The catalytic materials prepared by the co-precipitation method were calcined at 650 °C for 5 h (fresh samples); a portion of them was further treated at 750 °C for 7 h, in a furnace in static air (aged samples). Tests of methane combustion were carried out on fresh and aged catalysts at two different WHSV values (12 000 and 60 000 mL g−1 h−1). The catalytic performance of Co3O4/CeO2 and Co3O4/CeO2–ZrO2 were compared with those of two pure Co3O4 oxides, a sample obtained by the precipitation method and a commercial reference. Characterization studies by X-ray diffraction (XRD), BET and temperature-programmed reduction (TPR) show that the catalytic activity is related to the dispersion of crystalline phases, Co3O4/CeO2 and Co3O4/CeO2–ZrO2 as well as to their reducibility. Particular attention was paid to the thermal stability of the Co3O4 phase in the temperature range of 750–800 °C, in both static (in a furnace) and dynamic conditions (continuous flow). The results indicate that the thermal stability of the phase Co3O4 heated up to 800 °C depends on the size of the cobalt oxide crystallites (fresh or aged samples) and on the oxygen content (excess λ = 8, stoichiometric λ = 1) in the reaction mixture. A stabilizing effect due to the presence of ceria or ceria–zirconia against Co3O4 decomposition into CoO was observed. Moreover, the role of ceria and ceria–zirconia is to maintain a good combustion activity of the cobalt composite oxides by dispersing the active phase Co3O4 and by promoting the reduction at low temperature. 相似文献
6.
The physical, electronic and reactivity properties of bulk and supported Group V metal oxides (V, Nb, Ta and Db) were compared at the molecular level. Dubnium is a very short-lived element, 60 s, whose properties have not been extensively studied, but can be predicted from knowledge of the other members of the Group V metal oxides. Bulk V 2O 5 possesses platelet morphology with the active surface sites only located at the edges: primarily surface redox sites and some surface acidic sites. Bulk Nb 2O 5 and Ta 2O 5, as well as to be expected for bulk Db 2O 5, possess isotropic morphologies and the active surface sites relatively homogeneously dispersed over their surfaces: only surface acidic sites. However, the bifunctional bulk V 2O 5 was found to exhibit a much higher specific acidic catalytic activity than the acidic bulk Nb 2O 5 and Ta 2O 5, the latter being almost identical in their specific acidic catalytic activity. The bulk properties of the Group V metal oxides were essentially transferred to the analogous supported Group V metal oxides, where the active Group V metal oxides were present as a two-dimensional monolayer on various oxide supports (e.g., Al 2O 3, TiO 2, ZrO 2 as well as Nb 2O 5 and Ta 2O 5). For supported vanadia catalysts, the active surface sites were essentially redox sites, with the exception of supported V 2O 5/Al 2O 3 that also contained strong acidic sites. For supported niobia and tantala catalysts, as well as to be expected for supported dubnia catalysts, the active surface sites were exclusively acidic sites. However, the TOF redox for the supported vanadia catalysts and the TOF acidic for the supported niobia and tantala catalysts varied over several orders of magnitude as a function of the specific oxide support with the electronegativity of the oxide support cation. However, the TOF redox varied inversely to that of the TOF acidic variation because of the opposite requirements of these active surface sites. Surface redox sites are enhanced by reduction and surface acidic sites are enhanced by stabilization (lack of reduction). The current fundamental understanding of the Group V metal oxides allows for the molecular engineering of their metal oxide applied catalytic materials. 相似文献
7.
Cu-based spinel-oxides CuB 2O 4 (B = Fe, Mn, Cr, Ga, Al, or Fe 0.75Mn 0.25) were synthesized via a sol–gel method and subsequent solid-state reaction. The spinels mechanically mixed with γ-Al 2O 3 were evaluated for production of hydrogen from dimethyl ether steam reforming (DME SR). The reduction behavior and crystal property of these spinel-oxides, and the Cu oxidation state in spinel catalysts were investigated by temperature-programmed reduction, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The reduced phases of the Cu-based spinel catalysts that strongly affected the catalytic activity and durability were composed of metallic copper with metal oxides (MnO (B = Mn), Cr 2O 3 (B = Cr), and Al 2O 3 (B = Al)) or with spinels (CuGa 2O 4 (B = Ga), Fe 3O 4 (B = Fe), and MnFe 2O 4 (B = Fe 0.75Mn 0.25). The stability of B metal oxides and the interaction between copper species and B metal oxides significantly contributed to the reforming performance. 相似文献
8.
Ce xTi 1−xO 2 oxides have been synthesised by sol–gel method with x varying from 0 to 0.3 and characterised by XRD and TPR. The structure of oxides changes with the Ce/Ti molar ratio. The presence of ceria in Ce-Ti oxides inhibits the phase transition from anatase to rutile. When x = 0.3 (Ce 0.3Ti 0.7O 2 sample), the solid presents an amorphous state. The TPR results indicate that the presence of Ti enhances the reducibility of cerium oxide species. Catalytic oxidation of propene is investigated on Ce-Ti oxides and the better conversion is obtained with Ce 0.3Ti 0.7O 2 but the CO 2 selectivity reaches 63% at 400 °C. Gold is then deposited on theses oxides to improve the catalytic activity. On the basis of characterisation data (H 2 TPR), it has been suggested that gold influences the reduction of the Ce-Ti oxide support and the catalytic activity to the propene oxidation. Thus, Au/Ce-Ti-O system catalysts are promising catalysts for propene oxidation. 相似文献
9.
The performance of unpromoted and MO x-(M: alkali (earth), transition metal and cerium) promoted Au/Al 2O 3 catalysts have been studied for combustion of the saturated hydrocarbons methane and propane. As expected, higher temperatures are required to oxidize CH 4 (above 400 °C), compared with C 3H 8 (above 250 °C). The addition of various MO x to Au/Al 2O 3 improves the catalytic activity in both methane and propane oxidation. For methane oxidation, the most efficient promoters to enhance the catalytic performance of Au/Al 2O 3 are FeO x and MnO x. For C 3H 8 oxidation a direct relationship is found between the catalytic performance and the average size of the gold particles in the presence of alkali (earth) metal oxides. The effect of the gold particle size becomes less important for additives of the type of transition metal oxides and ceria. The results suggest that the role of the alkali (earth) metal oxides is related to the stabilization of the gold nanoparticles, whereas transition metal oxide and ceria additives may be involved in oxygen activation. 相似文献
10.
Nb 2O 5 loaded on the supports and mixed with oxides was studied to investigate the activity and acidity for Friedel-Crafts benzylation of anisole. From the study on the loaded catalysts, a preliminary conclusion for the selection of metal oxide was obtained; namely, such an acidic oxide as silica was suitable for the support of Nb 2O 5. Then, MoO 3 and WO 3 were mixed with Nb 2O 5, and prominent high catalytic activity and acidities were observed. Both oxides of Nb 2O 5-MoO 3 and Nb 2O 5-WO 3 showed almost similar behavior with respect to characterization and catalytic activity. Surface area increased, X-ray diffraction (XRD) and Raman bands were lost, acid sites, both Brønsted and Lewis characters generated, and surface acid site density was as high as 2–4 nm −2. The acid sites were generated on the amorphous metal oxides consisting of Nb and Mo or W oxides, different in nature from those of Nb 2O 5 calcined and un-calcined, and active for Friedel-Crafts benzylation. 相似文献
11.
The current work is devoted to study of CO interaction with PdO/Al 2O 3–(Ce x–Zr 1−x)O 2 catalysts. Ceria–zirconia–alumina supports with different Ce/Zr ratio were prepared by sol–gel technique. The FT-IR characterization of CO adsorbed at −120 and 25 °C on oxidized and reduced samples revealed that Ce/Zr ratio modifies the surface properties of support and oxidation state of palladium. The catalyst with Ce/Zr molar ratio 0.5/0.5 was characterized with the highest ability to stabilize palladium in oxide state and the highest activity to oxidize CO. Redox treatment of catalysts improves their catalytic activity. 相似文献
12.
Ag-modified La 0.6Sr 0.4MnO 3-based catalysts with the perovskite-type structure were prepared by using a citric acid sol–gel method, and their catalytic performance for complete oxidation of methanol and ethanol was evaluated and compared with that of the γ-Al 2O 3-supported catalysts, Ag/γ-Al 2O 3, Pt/γ-Al 2O 3, and Pd/γ-Al 2O 3. The results showed that the Ag-modified La 0.6Sr 0.4MnO 3-based catalysts with the perovskite-type structure displayed the activity significantly higher than that of the supported precious metal catalysts, 0.1%Pd/γ-Al 2O 3 and 0.1%Pt/γ-Al 2O 3 in the temperature range of 370–573 K. Over a 6%Ag/20%La 0.6Sr 0.4MnO 3/γ-Al 2O 3 catalyst, the T95 temperature for methanol oxidation can be as low as 413 K. Even at such low reaction temperature, there were little HCHO and CO detected in the reaction exit-gas. However, for the 0.1%Pd/γ-Al 2O 3 and 0.1%Pt/γ-Al 2O 3 catalysts, the HCHO content in the reaction exit-gas reached 200 and 630 ppm at their T95 temperatures. Over a 6%Ag/La 0.6Sr 0.4MnO 3 catalyst, the T95 temperature for ethanol oxidation can be as low as 453 K, with a corresponding content of CH 3CHO in the exit-gas at 782 ppm; when ethanol oxidation is performed at 493 K, the content of acetaldehyde in the exit-gas can be below 1 ppm. Characterization of the catalysts by X-ray diffraction (XRD), TEM, XPS, laser Raman spectra (LRS), hydrogen temperature-programmed reduction (H 2-TPR) and oxygen temperature-programmed desorption (O 2-TPD) methods revealed that both the surface and the bulk phase of the perovskite La 0.6Sr 0.4MnO 3 played important roles in the catalytic oxidation of the alcohols, and that γ-Al 2O 3 as the bottom carrier could be beneficial in creating a large surface area of catalyst. Moreover, a small amount of Ag + doped onto the surface of La 0.6Sr 0.4MnO 3 was able to partially occupy the positions of La 3+ and Sr 2+ due to their similar ionic radii, and thus, became stabilized by the perovskite lattice, which would be in favor of preventing the aggregation of the Ag species on the surface and enhancing the stability of the catalyst. On the other hand, modification of the Ag + to the surface of La 0.6Sr 0.4MnO 3 resulted in an increase in relative content of the surface O 22−/O − species highly reactive toward the alcohols and aldehydes as well as CO. Besides, solution of low-valence metal oxides SrO and Ag 2O with proper amounts in the lattice of the trivalent metal perovskite-type oxide LaMnO 3 would also lead to an increase in the content of the reducible Mn n+ and the formation of anionic vacancies, which would be favorable for the adsorption-activation of oxygen on the functioning catalyst and the transport of the lattice and surface oxygen species. All these factors would contribute to the pronounced improvement of the catalyst performance. 相似文献
13.
La xSr 2−xMnO 4 (0 ≤ x ≤ 0.8) oxides were synthesized and single-phase K 2NiF 4-type oxides were obtained in the range of 0.1 ≤ x < 0.5. The catalytic activity of La xSr 2−xMnO 4 for NO–CO reaction increased with increasing x in the range of solubility limit of La. La 0.5Sr 1.5MnO 4 showed the highest activity among La xSr 2−xMnO 4 prepared in this study, but its activity was inferior to perovskite-type La 0.5Sr 0.5MnO 3. Among the Pd-loaded catalysts, however, Pd/La 0.8Sr 1.2MnO 4 showed the higher activity and the selectivity to N 2 than Pd/La 0.5Sr 0.5MnO 3 and Pd/γ-Al 2O 3. The excellent catalytic performance of Pd/La 0.2Sr 1.2MnO 4 could be ascribable to the formation of SrPd 3O 4 which was detected by XRD in the catalyst but not in the other two catalysts. 相似文献
14.
The gliding arc discharge, combined with a catalytic bed, has been applied for nitrous oxide processing in oxygen containing gases. It has been found that under conditions of the gliding arc, nitrous oxide in mixtures with oxygen or air not only decomposes to oxygen and nitrogen, but is also oxidised to nitric oxide. The overall conversion of nitrous oxide, as well as the degree of N 2O oxidation to NO were studied as a function of its initial concentration, flow rate, and discharge power. The overall N 2O conversion and degree of oxidation to NO decreased with increasing flow rate and initial N 2O concentration, and increased with increasing discharge power. The degree of N 2O oxidation to NO varied within 20–37%. The overall conversion and degree of N 2O oxidation increased when granular dielectric materials (TiO 2, SiO 2 (quartz glass), and γ-Al 2O 3) were introduced into the reaction zone. The energy efficiency and the overall conversion of N 2O were still further increased due to catalytic effects of a number of metal oxides (CuO, NiO, MnO 2, Fe 2O 3, Co 3O 4, ZrO 2) deposited on γ-Al 2O 3. The activity of the oxide catalysts within the active power range of 300–360 W decreased in the order: CuO>Fe 2O 3>NiO>MnO 2>Co 3O 4>ZrO 2. It has been concluded that the combined plasma-catalytic processing may be an efficient way for the reduction of N 2O emissions. 相似文献
15.
分别以Cu(NO_3)_2·3H_2O和50%Mn(NO_3)_2水溶液为铜源和锰源,K_2CO_3为沉淀剂,采用沉淀法和共沉淀法制备单一Cu、Mn氧化物催化剂和Cu-Mn-O复合氧化物催化剂,用于催化N_2O直接分解反应,并利用N_2物理吸附-脱附、XRD、FT-IR和TPR等进行表征。结果表明,单一Cu和Mn氧化物分别以体相CuO和Mn2O_3物相形式存在,Cu-Mn-O复合氧化物中除形成CuMn_2O_4尖晶石物相外,还有一定量小晶粒CuO,较单一氧化物具有更加优异的还原性能,表现出较高的催化N_2O直接分解活性。在空速10 000 h~(-1)和N_2O体积分数0.1%条件下,Cu-Mn-O复合氧化物催化剂可在440℃催化N_2O完全分解,分别较单一Cu和Mn氧化物催化剂降低了40℃和60℃。 相似文献
16.
Co 3O 4/CeO 2 composite oxides with different cobalt loading (5, 15, 30, 50, 70 wt.% as Co 3O 4) were prepared by co-precipitation method and investigated for the oxidation of methane under stoichiometric conditions. Pure oxides, Co 3O 4 and CeO 2 were used as reference. Characterization studies by X-ray diffraction (XRD), BET, temperature programmed reduction/oxidation (TPR/TPO) and X-ray photoelectron spectroscopy (XPS) were carried out. An improvement of the catalytic activity and thermal stability of the composite oxides was observed with respect to pure Co3O4 in correspondence of Co3O4–CeO2 containing 30% by weight of Co3O4. The combined effect of cobalt oxide and ceria, at this composition, strongly influences the morphological and redox properties of the composite oxides, by dispersing the Co3O4 phase and promoting the efficiency of the Co3+–Co2+ redox couple. The presence in the sample Co3O4(30 wt.%)–CeO2 of a high relative amount of Ce3+/(Ce4+ + Ce3+) as detected by XPS confirms the enhanced oxygen mobility. The catalysts stability under reaction conditions was investigated by XRD and XPS analysis of the used samples, paying particular attention to the Co3O4 phase decomposition. Methane oxidation tests were performed over fresh (as prepared) and thermal aged samples (after ageing at 750 °C for 7 h, in furnace). The resistance to water vapour poisoning was evaluated for pure Co3O4 and Co3O4(30 wt.%)–CeO2, performing the tests in the presence of 5 vol.% H2O. A methane oxidation test upon hydrothermal ageing (flowing at 600 °C for 16 h a mixture 5 vol.% H2O + 5 vol.%O2 in He) of the Co3O4(30 wt.%)–CeO2 sample was also performed. All the results confirm the superiority of this composite oxide. 相似文献
17.
The selective catalytic reduction of nitric oxide with ammonia was studied using Fe 2O 3, Cr 2O 3 and CuO loaded active carbons as catalysts in the presence and absence of oxygen at reaction temperatures between 100 and 500°C. Active carbons pretreated with concentrated nitric acid showed a higher catalytic activity in SCR than catalysts which were oxidized in air. The ash content (from 0.2 to 7.1 wt.%) of different unloaded active carbons had no effect on the catalytic activity below 300°C in the absence of oxygen. However, in the presence of oxygen an increasing ash content resulted in an increase in activity. Transition-metal oxide loading led to an increase in SCR activity, especially in the absence of oxygen. An increasing transition-metal content from 1 to 10 wt.% improved the activity as well. The presence of oxygen in the reaction mixture enhanced the conversion of nitric oxide especially in the low-temperature range between 100 and 200°C. Activity and selectivity of the respective catalysts were influenced by the type of metal oxide: in the presence of oxygen, catalysts with 10 wt.% Fe were the most active and selective. 相似文献
18.
Catalytic wet air oxidation (CWAO) of phenol with iron/activated carbon catalysts (Fe/AC) at temperature of 400 K and 8 atm of total pressure is an efficient treatment to oxidize a resistant pollutant such as phenol into biodegradable species, mainly short chain acids. Extended studies employing activated carbon catalysts point out significant changes in the carbon as a consequence of the CWAO process. After the long-term experiments carried out in this work it was concluded that these modifications consist of loss of microporosity, temporary decrease of the mesoporosity, decrease of the carbon/oxygen ratio on the catalyst surface, more acidic pH slurry values, and aggregation of the -Fe 2O 3 crystallites. The causes that provoke these changes and the reasons why they do not alter significantly the CWAO efficiency were analyzed. The way of exposition of Fe/AC catalyst to the reactants plays an important role in its activity and selectivity towards complete mineralization, namely oxidation to CO 2 and H 2O. 相似文献
19.
In this study, catalysts containing 0.5 wt.% of palladium or 5 wt.% of copper were compared towards toluene total oxidation using FAU Zeolite and ZrO 2 supports. A 0.5%Pd/NaFAU and 5%Cu/ZrO 2 were found to be promising catalysts for this reaction. Palladium presented then a better affinity for FAU zeolite and copper oxide had a better affinity for zirconia. The performances of Pd based catalysts were correlated to interaction between the active phase and the support whereas the activity of copper oxide was related to oxygen mobility property of the support leading to copper oxide particles easily reducible. Support modifications, yttrium addition for ZrO 2 and cation exchange for the zeolite FAU, still enhanced the catalytic activity. Therefore, 0.5%Pd/CsFAU and 5%Cu/Zr 95Y 5 samples were found to be interesting catalysts for total VOC oxidation. 相似文献
20.
Heterogeneous catalysts based on magnetic mixed iron oxides (MO·Fe 2O 3; M: Fe, Co, Cu, Mn) were used for the decolorization of several synthetic dyes (Bromophenol Blue, Chicago Sky Blue, Cu Phthalocyanine, Eosin Yellowish, Evans Blue, Naphthol Blue Black, Phenol Red, Poly B-411, and Reactive Orange 16). All the catalysts decomposed H 2O 2 yielding highly reactive hydroxyl radicals, and were able to decolorize the synthetic dyes. The most effective catalyst FeO·Fe 2O 3 (25 mg mL −1 with 100 mmol L −1 H 2O 2) produced more than 90% decolorization of 50 mg L −1 Bromophenol Blue, Chicago Sky Blue, Evans Blue and Naphthol Blue Black within 24 h. The fastest decomposition proceeded during the first hour of the reaction. In addition to dye decolorization, all the catalysts also caused a significant decrease of chemical oxygen demand (COD). Individual catalysts were active in the pH range 2–10 depending on their structure and were able to perform sequential catalytic cycles with low metal leaching. 相似文献
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