Oxygen Storage in Transition Metal-Doped Bixbyite Vanadium Sesquioxide Nanocrystals

2020 ◽  
Author(s):  
Lauren Reimnitz ◽  
Thiri Lwin ◽  
Mario Lopez ◽  
Delia Milliron
Keyword(s):  
Storage Capacity ◽  
Degradation Products ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
Vanadium Sesquioxide ◽  
Doped Materials ◽  
Metal Doped

<p>Bixbyite vanadium sesquioxide (V<sub>2</sub>O<sub>3</sub>) is a metastable polymorph of vanadium oxide that has been shown to have a significant oxygen storage capacity with very low temperature oxidation onset. In this work, bixbyite V<sub>2</sub>O<sub>3</sub> nanocrystals were synthesized with titanium and manganese dopants. Doped materials with varied dopant concentration were synthesized, and all were incorporated as aliovalent metal ions. The oxygen storage capacity of these nanocrystal materials was evaluated over ten oxidation and reduction cycles. It was found that over these ten cycles, the oxygen storage capacity of all the materials fell drastically. <i>In situ</i> X-ray diffraction evidence shows that manganese-doped materials degrade into an amorphous manganese-containing vanadate, while titanium-doped materials form crystalline degradation products. In all cases, this degradation causes an increase in the minimum mass achieved during oxygen release, indicating irreversible oxidation. </p>

Oxygen Storage in Transition Metal-Doped Bixbyite Vanadium Sesquioxide Nanocrystals

2020 ◽  
Author(s):  
Lauren Reimnitz ◽  
Thiri Lwin ◽  
Mario Lopez ◽  
Delia Milliron
Keyword(s):  
Storage Capacity ◽  
Degradation Products ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
Vanadium Sesquioxide ◽  
Doped Materials ◽  
Metal Doped

<p>Bixbyite vanadium sesquioxide (V<sub>2</sub>O<sub>3</sub>) is a metastable polymorph of vanadium oxide that has been shown to have a significant oxygen storage capacity with very low temperature oxidation onset. In this work, bixbyite V<sub>2</sub>O<sub>3</sub> nanocrystals were synthesized with titanium and manganese dopants. Doped materials with varied dopant concentration were synthesized, and all were incorporated as aliovalent metal ions. The oxygen storage capacity of these nanocrystal materials was evaluated over ten oxidation and reduction cycles. It was found that over these ten cycles, the oxygen storage capacity of all the materials fell drastically. <i>In situ</i> X-ray diffraction evidence shows that manganese-doped materials degrade into an amorphous manganese-containing vanadate, while titanium-doped materials form crystalline degradation products. In all cases, this degradation causes an increase in the minimum mass achieved during oxygen release, indicating irreversible oxidation. </p>

CO Oxidation over Pd Catalysts Supported on Different Supports: A Consideration of Oxygen Storage Capacity of Catalyst

2011 ◽  
Vol 347-353 ◽  
pp. 3298-3301
Author(s):  
Ye Xu ◽  
Jin Qiang Ma ◽  
Yuan Feng Xu ◽  
Hui Li ◽  
He Xing Li ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
Pd Catalysts ◽  
Transmission Electron ◽  
Pulse Experiment ◽  
Temperature Programmed

A series of Pd catalysts supported on different materials (SiO2, γ-Al2O3, CeO2, TiO2) were synthesized through precipitation reduction of palladium ions with H2. They exhibited different activity during catalytic oxidation of CO to CO2. With the characterization of N2 physisorption experiment, X-ray diffraction, transmission electron microscopy, temperature-programmed reduction, and CO and O2 multi-pulse experiment, the correlation of catalytic activity and oxygen storage capacity (OSC) of catalyst has been investigated. It was found that the reactivity is largely controlled by the OSC of the catalysts, and thus Pd/CeO2 and Pd/TiO2 were more active than Pd/SiO2 and Pd/Al2O3 for CO oxidation.

Synthesis and Characterization of Ce0.5Zr0.5O2 Nanocomposite and its Supported Pd-Only Catalysis Activity

2014 ◽  
Vol 633 ◽  
pp. 77-81
Author(s):  
Dong Xia Yang ◽  
Ping Ning ◽  
Jie Li He ◽  
Jing Fang Zhu ◽  
Ting Ting Zheng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
Fractional Precipitation ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Redox Ability

The Ce0.5Zr0.5O2 nanocomposites (CZ) were prepared by co-precipitation(CP), fractional precipitation (FP) and fractional precipitation with hydrothermal treatment (FP-HT). The samples were characterized by X-ray diffraction (XRD), Brunauer-Emmet Teller method (BET), H2-temperature programmed reduction (H2-TPR), and thermogravimetric analysis (TG) under H2-N2. XRD results displayed that all samples formed a single solid solution-like ceria-zirconia phase. BET results revealed CZ prepared by FP-HT (CZ-FP-HT) had the highest surface area. H2-TPR and TG analysis under H2-N2 showed CZ-FP-HT exhibited the strongest redox ability and oxygen storage capacity. Moreover, three-way catalysts of Pd-Rh supported on CZ -FP-HT and commercial CZ with same composites were prepared, and their three-way catalytic activity were also studied by engine evaluation. Pd-Rh/CZ-FP-HT showed a bit of higher oxygen storage capacity, catalytic activity and better thermal stability than Pd-Rh/CZ-commercial.

scholarly journals Effect of Sr on the properties of Ce-Zr-La mixed oxides

2006 ◽  
Vol 71 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Richuan Rao ◽  
LI Lianyong ◽  
LI Fengyi
Keyword(s):  
Mixed Oxide ◽  
Storage Capacity ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
Pulse Technique ◽  
X Ray ◽  
Good Thermal Stability

Ce-Zr-La-Sr mixed oxides, with different Sr contents, were prepared by the sol-gel method. In a flow-system microreactor, the reduction properties and the oxygen storage capacity (OSC) of the Ce-Zr-La-Sr mixed oxides were investigated by a temperature programmed reduction (TPR) and a pulse technique. It was shown that the properties of the Ce-Zr-La mixed oxides depend on the Sr content and that the optimum Sr content in the Ce-Zr-La-Sr mixed oxide is 3 mol%. The Ce-Zr-La-Sr mixed oxides doped with 3 mol% Sr (Ce0.52Zr0.4La0.05Sr0.03O1.945) has the largest specific surface area and better reduction properties and oxygen storage capacity in comparison to the other investigated samples. The XRD results of the Ce-Zr-La-Sr mixed oxides showed that their X-ray diffraction patterns are well in agreement with that of fluorite-type CeO2 with Sr ions incorporated into the Ce-Zr-La mixed oxide structures. With increasing calcination temperature, the intensity of the X-ray diffraction peaks increased, but no new peaks were observed. All of these indicate that the synthesized samples had good thermal stability.

Synthesis and Characterization of CeO2-ZrO2-Al2O3 with High Thermal Stability and Oxygen Storage Capacity from Pseudoboehmite Precursor

2012 ◽  
Vol 463-464 ◽  
pp. 160-164
Author(s):  
Dong Zhang
Keyword(s):  
Thermal Stability ◽  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Alumina Oxide ◽  
Composite Solid

The surface and structural properties, thermal stability and oxygen storage capability are inverstigated in ceria-zirconia-alumina oxide with deposition coprecipitation method using the Pseudoboehmite precursor. X-ray diffraction (XRD), Brunauer-Emmet Teller method (BET), Transmission electron microscopy (TEM) and oxygen pulsing technique are used to character the prepared materials. The prepared ceria-zirconia-alumina oxides are highly dispersed composite solid solution. After calcination at 650 °C and 1000 °C respectively, these compounds can still keep the structural and textural stability and hold excellent oxygen storage capability.

Autothermal Reforming of Propane Over Ni Catalysts Supported on a Variety of Perovskites

2007 ◽  
Vol 7 (11) ◽  
pp. 4013-4016 ◽  
Author(s):  
SeungSoo Lim ◽  
DongJu Moon ◽  
JongHo Kim ◽  
YoungChul Kim ◽  
NamCook Park ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Storage Capacity ◽  
Flow Reactor ◽  
Oxygen Storage Capacity ◽  
Autothermal Reforming ◽  
Oxygen Storage ◽  
Hydrogen Yield ◽  
Impregnation Method ◽  
Ni Catalysts ◽  
Atmospheric Flow

Autothermal reforming of propane for hydrogen over Ni catalysts supported on a variety of perovskites was performed in an atmospheric flow reactor. Perovskite is known for its higher thermal stability and oxygen storage capacity, but catalytic activity of itself is low. A sites of the ABO3 structured perovskites were occupied by La while B sites by one of Fe, Co, Ni, and Al by citrate method. The composition of the reactant mixture was H2O/C/O2 = 8.96/1.0/1.1. The changes in the states of the catalysts after reaction were analyzed by XRD, TPD, and TGA. Ni/LaAlO3 catalyst maintained the perovskite structure after reaction. It showed higher hydrogen yield and thermal stability compared to those of the catalysts with Fe, Co, or Ni in B sites. Catalysts prepared by deposition-precipitation (DP) method showed higher activity than those prepared by impregnation method, presumably due to the smaller sizes of the NiO crystal particles.

Mn3O4 doped with highly dispersed Zr species: a new non-noble metal oxide with enhanced activity for three-way catalysis

2016 ◽  
Vol 40 (12) ◽  
pp. 10108-10115 ◽  
Author(s):  
Genyuan Zhao ◽  
Jing Li ◽  
Wenshuang Zhu ◽  
Xueqin Ma ◽  
Yonghua Guo ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Manganese Oxide ◽  
Noble Metal ◽  
Storage Capacity ◽  
Catalytic Properties ◽  
Oxygen Storage Capacity ◽  
Oxide Catalysts ◽  
Oxygen Storage ◽  
Highly Dispersed ◽  
Three Way Catalysis

Herein, we demonstrate the influence of zirconium species on promoting the oxygen storage capacity and three-way catalytic properties of zirconium-manganese oxide catalysts.

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