Catalytic destruction of chlorobenzene over mesoporous ACeOx (A=Co, Cu, Fe, Mn, or Zr) composites prepared by inorganic metal precursor spontaneous precipitation

Abstract

Mesostructured ACeO x (A = Co, Cu, Fe, Mn, or Zr) composites with large specific surface area and developed mesoporosity were prepared by inorganic metal precursor spontaneous precipitation (IMSP) method. Influences of catalyst surface area, pore structure, reducibility, and active oxygen concentration on catalytic performance were studied. Both preparation route and metal precursor type affect metal active site dispersion, and the IMSP is a desirable approach for synthesis of metal composites with homogeneous active phase distribution. The original crystalline structure of CeO 2 is well maintained although parts of transition metal cations are incorporated into its framework. The forming of A n+ -O 2− -Ce 4+ connections in ACeO x catalysts could reduce the redox potential of metal species, allowing effective redox cycles during oxidation reactions. CuCeO x demonstrates powerful catalytic efficiency with 99% of chlorobenzene (CB) destructed at 328°C, which is much lower than the other ACeO x oxides and Cu-doped catalysts synthesized via the incipient impregnation and coprecipitation methods (T 99 N 405°C). The active site reducibility is the foremost activity determining factor for CB destruction.

Evaluation of the Efficiency of Detection and Capture of Manganese in Aqueous Solutions of FeCeOx Nanocomposites Doped with Nb2O5

“…Additionally, the use of iron-containing nanoparticles or composites based on them is accompanied by a rapid rate of degradation of the crystal structure as a result of the oxidation of iron and its subsequent decay. One way to increase resistance to degradation, as well as changes in functional properties and surface is to dope nanocomposites FeCeO x various elements or compounds, which significantly increases their productivity, as well as structural and morphological properties [ 16 , 17 , 18 , 19 , 20 ].…”

Catalytic Degradation of Benzene over Nanocatalysts containing Cerium and Manganese

“…The peaks at 239 and 360 °C are attributed to the reduction of Mn 3+ , with an area ratio of the lower to the higher temperature hydrogen consumption of about 1:2. This is a typical feature of the two‐step reduction of Mn 2 O 3 ; the low‐temperature reduction peak (239 °C) represents the reduction of Mn 2 O 3 to Mn 3 O 4 and the high‐temperature reduction peak (360 °C) referrs to the further reduction of Mn 3 O 4 to MnO . The peak at 316 °C may be caused by the synergistic effect between Mn 3+ and Ce 4+ , which would result in the highest activity for VOC oxidation .…”

“…This is at ypical feature of the two-step reduction of Mn 2 O 3 ;the low-temperature reduction peak (239 8C) represents the reduction of Mn 2 O 3 to Mn 3 O 4 and the high-temperature reductionp eak (360 8C) referrs to the further reduction of Mn 3 O 4 to MnO. [35] The peak at 316 8Cm ay be caused by the synergistic effect between Mn 3 + andC e 4 + ,w hich would result in the highest activity for VOC oxidation. [36] Thep eak at 683 8Ci sa ssigned to the bulk oxygen speciesr eduction of the CeO 2 phase, according to the TPR pattern of CeO 2 ,a ss hown in Figure S1 of the SupportingI nformation.…”

“…For PdO/Ce 0.3 Mn 0.7 ,t he reduction peak with the highest intensity was recordeda t8 78C, which may be attributed to the reduction of Pd 2 + speciesa nd interaction between the active phase and supports. [35,37] The peaks at 418 and6 94 8Ca re attributedt ot he reduction of surfaceo xygen and bulk oxygen in the CeO 2 phaseo ft he support, respectively.C ompared with Ce 0.3 Mn 0.7 ,t he reduction of the supportings ample starts at ar elative low temperature, which indicates that the redox nature of the support is enhanced upon the addition of the active phase and the existence of interactions. In addition, the peak at 240 8C, corresponding to the reduction of Mn 3 + ,i sa lso observed;h owever,t he intensity of the peak is weakw hen comparing with that of Ce 0.3 Mn 0.7 ,i ndicatingt hat the interaction between the active component and the supporter influences the reduction of Mn 3 + .…”

Syntheses of Hierarchical MnO2via H2O2 Selectively Reducing KMnO4 for Catalytic Combustion of Toluene

“…The possessing properties of manganese oxides also make it exhibit good catalytic activities for the removal of gaseous pollutant such as CO, NOx and volatile organic compounds (VOCs), as well as cheap and easily‐obtained catalysts compared to noble‐metal catalysts . Therefore, much attention has been paid to manganese oxides materials . The improved performances of manganese oxides are closely related to the average oxidation state, redox potential and specific surface area of oxides, which may be dramatically affected by synthetic conditions.…”