Abstract:The same amount of
metal was deposited on the surface of three-dimensional
mesoporous MCM-48 by a facile impregnation–calcination method
for catalytic ozonation of pharmaceutical and personal-care products
in the liquid phase. At 120 min reaction time, Co/MCM-48 and Ce/MCM-48
showed 46.6 and 63.8% mineralization for clofibric acid (CA) degradation,
respectively. Less than 33% mineralization was achieved with Co/MCM-48
and Ce/MCM-48 during sulfamethazine (SMZ) ozonation. In the presence
of monometallic oxides m… Show more
“…For the CeO 2 /Co 3 O 4 samples with loading levels higher than 5 wt %, other broad peaks (λ) located at higher reduction temperatures can be ascribed to the reduction of surface CeO 2 species weakly interacting with Co 3 O 4 . It should be noted that among the series of binary metal oxides, CeO 2 /Co 3 O 4 -3 with good redox property and abundant oxygen vacancies presents the lowest initiating and peak-maximum temperatures, suggesting its excellent reducibility and higher mobility of lattice oxygen . Recent studies have illustrated that catalysts with better reducibility can facilitate the generation of more easily redox species and more active oxygen species for the oxidation reactions. , …”
Section: Resultsmentioning
confidence: 99%
“…It should be noted that among the series of binary metal oxides, CeO 2 /Co 3 O 4 -3 with good redox property and abundant oxygen vacancies presents the lowest initiating and peakmaximum temperatures, suggesting its excellent reducibility and higher mobility of lattice oxygen. 53 Recent studies have illustrated that catalysts with better reducibility can facilitate the generation of more easily redox species and more active oxygen species for the oxidation reactions. 34,54 The activation of O 2 is a very crucial factor for the redox reactions.…”
An ideal catalytic process for the
selective oxidation of hydrocarbons
should employ an efficient, recyclable, and cost-effective catalyst
under solvent- and additive-free conditions with molecular oxygen
as the only oxidant. This is an important goal in the catalysis community
and remains a significant challenge. In this respect, we report the
facile construction of a series of uniform CeO2 nanoparticle-decorated
Co3O4 microspheres (CeO2/Co3O4) for the selective ethylbenzene oxidation reaction
by molecular oxygen. Among the catalysts with various CeO2 loading levels, CeO2/Co3O4-3 (5
wt % loading of CeO2) obtained by careful composition modulation
exhibits the optimum reaction performance, with ethylbenzene conversion
of 73.4% accompanied by a selectivity of 78.5% to acetophenone. The
yield of acetophenone can achieve 57.6%, while the reaction rate can
reach up to 401.3 mmol gcat
–1 h–1. In addition, CeO2/Co3O4-3 presents
robust stability and good recycling performance. The tailored CeO2/Co3O4-3 catalyst is superior to the
reported catalysts, and it is the state-of-the-art catalyst under
the current challenging reaction system. Experimental evidence and
mechanism analysis suggest that the interface synergy featured with
−Ce–OV–Co– active sites derived
from the intimate connection between the two oxides is the dominant
contributor in boosting the catalytic performance. This work can reinvigorate
research into the exploitation of catalysts for the sustainable and
green catalytic oxidation of ethylbenzene and beyond.
“…For the CeO 2 /Co 3 O 4 samples with loading levels higher than 5 wt %, other broad peaks (λ) located at higher reduction temperatures can be ascribed to the reduction of surface CeO 2 species weakly interacting with Co 3 O 4 . It should be noted that among the series of binary metal oxides, CeO 2 /Co 3 O 4 -3 with good redox property and abundant oxygen vacancies presents the lowest initiating and peak-maximum temperatures, suggesting its excellent reducibility and higher mobility of lattice oxygen . Recent studies have illustrated that catalysts with better reducibility can facilitate the generation of more easily redox species and more active oxygen species for the oxidation reactions. , …”
Section: Resultsmentioning
confidence: 99%
“…It should be noted that among the series of binary metal oxides, CeO 2 /Co 3 O 4 -3 with good redox property and abundant oxygen vacancies presents the lowest initiating and peakmaximum temperatures, suggesting its excellent reducibility and higher mobility of lattice oxygen. 53 Recent studies have illustrated that catalysts with better reducibility can facilitate the generation of more easily redox species and more active oxygen species for the oxidation reactions. 34,54 The activation of O 2 is a very crucial factor for the redox reactions.…”
An ideal catalytic process for the
selective oxidation of hydrocarbons
should employ an efficient, recyclable, and cost-effective catalyst
under solvent- and additive-free conditions with molecular oxygen
as the only oxidant. This is an important goal in the catalysis community
and remains a significant challenge. In this respect, we report the
facile construction of a series of uniform CeO2 nanoparticle-decorated
Co3O4 microspheres (CeO2/Co3O4) for the selective ethylbenzene oxidation reaction
by molecular oxygen. Among the catalysts with various CeO2 loading levels, CeO2/Co3O4-3 (5
wt % loading of CeO2) obtained by careful composition modulation
exhibits the optimum reaction performance, with ethylbenzene conversion
of 73.4% accompanied by a selectivity of 78.5% to acetophenone. The
yield of acetophenone can achieve 57.6%, while the reaction rate can
reach up to 401.3 mmol gcat
–1 h–1. In addition, CeO2/Co3O4-3 presents
robust stability and good recycling performance. The tailored CeO2/Co3O4-3 catalyst is superior to the
reported catalysts, and it is the state-of-the-art catalyst under
the current challenging reaction system. Experimental evidence and
mechanism analysis suggest that the interface synergy featured with
−Ce–OV–Co– active sites derived
from the intimate connection between the two oxides is the dominant
contributor in boosting the catalytic performance. This work can reinvigorate
research into the exploitation of catalysts for the sustainable and
green catalytic oxidation of ethylbenzene and beyond.
“…The broad peak at 15° < 2θ < 30° was observed for all catalysts, corresponding to the amorphous silica phase. The broad peak intensity of Co(1)/MS, Co(2)/MS, and Co(3)/MS decreased with increasing cobalt concentration [19]. This indicates that the impregnation of metal slightly reduced the amorphous area.…”
The analysis of the effect of cobalt concentration supported on mesoporous silica (MS) has been evaluated. This study was aimed to observe the physical and chemical characteristics of the catalysts, and also to study the catalytic activity and its selectivity towards gasoline and diesel oil products in the hydrocracking process of waste coconut oil. The MS was produced using Lapindo mud, where the CTAB was used as the mesopore templating agent. The Co/MS catalyst was prepared by the wet impregnation method with various concentrations of Co. The characterization of the catalyst includes silica purity test by XRF, determination of Co content by AAS, the crystallinity by XRD, the catalyst porosity by SAA, physical pore structure by SEM and TEM, and total acidity by the gravimetric method using NH3 base vapor adsorption. The hydrocracking was carried out in a hydrocracking reactor using various concentrations of Co/MS catalysts with the ratio of catalyst/feed = 1/50. The products of the hydrocracking process were liquid, coke, and gas. The composition of the hydrocracking liquid products was analyzed by GC-MS. Based on the results of the catalytic activity test, it was concluded that the Co(1)/MS catalyst, which had the highest acidity, showed the best catalyst selectivity towards gasoline and diesel fractions.
“…Many efforts have been focused on developing efficient and practical catalysts for HCO, and up to the present, a number of transition-metal oxides have been reported to be active toward HCO. − However, few meet the criteria for an excellent HCO catalyst: high activity, good stability, wide applicable pH range, low leaching of metal ions, easy dispersion in and separation from water, and good recyclability. Therefore, the design and synthesis of new catalysts that meet all the requirements of HCO are still a promising but challenging task.…”
Copper foam (CF)-supported Cu
x
O@Fe2O3 core–shell nanotubes (CF/Cu
x
O@Fe2O3 NTs) were synthesized
as a hybrid catalyst for heterogeneous catalytic ozonation (HCO).
The hybrid catalyst exhibits high activity and excellent stability
for the HCO of organic pollutants. The total organic carbon removal
rates of methyl orange, ibuprofen, and nitrobenzene via HCO were 89,
82, and 88%, respectively, which are over 2 times higher than the
corresponding values obtained without the catalyst. The hybrid catalyst
also displays wide pH operation range, low metal leaching, easy separation
from treated water, and excellent recyclability. We prove that large
amounts of Lewis acid sites with medium acidity are created at the
Cu
x
O/Fe2O3 interface
due to the synergic effect of Cu
x
O and
Fe2O3. These medium acid sites are the main
active centers for the production of free hydroxyl radicals (•OH) and superoxide radicals (O2
•– or HO2
•) in neutral solution. Moreover,
the 3D porous framework of the catalyst enables easy dispersion in
and separation from water. This work develops a new strategy to design
HCO catalysts by combining strong and weak Lewis acid oxides and also
opens a new avenue for developing HCO catalysts on a 3D porous framework.
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