Mechanistic insights into the phase transition and metal ex-solution phenomena of Pr0.5Ba0.5Mn0.85Co0.15O3−δ from simple to layered perovskite under reducing conditions and enhanced catalytic activity

2021 ◽  
Author(s):  
Kyeounghak Kim ◽  
Sangwook Joo ◽  
Rui Huang ◽  
Hyung Jun Kim ◽  
Guntae Kim ◽  
...  
Keyword(s):  
Phase Transition ◽  
Catalytic Activity ◽  
Oxygen Vacancies ◽  
Layered Perovskite ◽  
Reducing Conditions ◽  
Selective Formation

The selective formation of oxygen vacancies plays a key role in the phase transition to layered perovskite with B-metal ex-solution.

scholarly journals Highly Dispersed Pd Species Supported on CeO2 Catalyst for Lean Methane Combustion: The Effect of the Occurrence State of Surface Pd Species on the Catalytic Activity

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 772
Author(s):  
Yanxiong Liu ◽  
Changhua Hu ◽  
Longchun Bian
Keyword(s):  
Catalytic Activity ◽  
Oxygen Vacancies ◽  
Methane Combustion ◽  
Pd Nanoparticles ◽  
High Concentration ◽  
Ch4 Combustion ◽  
Highly Active ◽  
Δ Phase ◽  
Occurrence State ◽  
Comprehensive Characterization

The correlation between the occurrence state of surface Pd species of Pd/CeO2 for lean CH4 combustion is investigated. Herein, by using a reduction-deposition method, we have synthesized a highly active 0.5% PdO/CeO2-RE catalyst, in which the Pd nanoparticles are evenly dispersed on the CeO2 nanorods CeO2-R. Based on comprehensive characterization, we have revealed that the uniformly dispersed Pd nanoparticles with a particle size distribution of 2.3 ± 0.6 nm are responsible for the generation of PdO and PdxCe1−xO2−δ phase with –Pd2+–O2−–Ce4+– linkage, which can easily provide oxygen vacancies and facilitate the transfer of reactive oxygen species between the CeO2-R and Pd species. As a consequence, the remarkable catalytic activity of 0.5% Pd/CeO2-RE is related to the high concentration of PdO species on the surface of the catalyst and the synergistic interaction between the Pd species and the CeO2 nanorod.

scholarly journals On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 312 ◽  
Author(s):  
Antonella Glisenti ◽  
Andrea Vittadini
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Formation Energy ◽  
Oxygen Vacancies ◽  
Catalytic Performance ◽  
Energy Profiles ◽  
High Concentrations ◽  
3D Impurities

The effects of modifying the composition of LaCoO3 on the catalytic activity are predicted by density functional calculations. Partially replacing La by Sr ions has benefical effects, causing a lowering of the formation energy of O vacancies. In contrast to that, doping at the Co site is less effective, as only 3d impurities heavier than Co are able to stabilize vacancies at high concentrations. The comparison of the energy profiles for CO oxidation of undoped and of Ni-, Cu-m and Zn-doped (La,Sr)CoO3(100) surface shows that Cu is most effective. However, the effects are less spectacular than in the SrTiO3 case, due to the different energetics for the formation of oxygen vacancies in the two hosts.

scholarly journals Selective formation of apical oxygen vacancies in La2−xSrxCuO4

2017 ◽  
Vol 1 (5) ◽  
Author(s):  
Gideok Kim ◽  
Georg Christiani ◽  
Gennady Logvenov ◽  
Sungkyun Choi ◽  
Hun-Ho Kim ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Apical Oxygen ◽  
Selective Formation

Effects of rare earth metal doping on Au/ReZrO2 catalysts for efficient hydrogen generation from formic acid

2021 ◽  
Vol 45 (12) ◽  
pp. 5704-5711
Author(s):  
Luming Wu ◽  
Yu Hao ◽  
Shaohua Chen ◽  
Rui Chen ◽  
Pingchuan Sun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rare Earth ◽  
Rare Earth Metal ◽  
Oxygen Vacancies ◽  
Hydrogen Generation ◽  
Earth Metal ◽  
Support Interaction ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Metal Doped

Rare earth metal doped ZrO2 can promote the formation of oxygen vacancies in zirconia, which enhances the metal–support interaction, finally promoting catalytic activity of FA dehydrogenation.

Remarkable Activity of Nanoarchitectonics Mesoporous CuO/CeO2–TiO2 Prepared by Nanocasting and Deposition Precipitation Techniques

2020 ◽  
Vol 20 (5) ◽  
pp. 2791-2802
Author(s):  
Duangamol Ongmali ◽  
Sakollapath Pithakratanayothin ◽  
Sureerat Jampa ◽  
Apanee Luengnaruemitrchai ◽  
Thanyalak Chaisuwan ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Crystallite Size ◽  
Oxygen Vacancies ◽  
Redox Properties ◽  
Oxygen Defect ◽  
Nitrate Salt ◽  
Hard Template ◽  
Different Levels

In this work, a ceria (CeO2) support was modified with titania (TiO2) by nanocasting using MCM-48 as a hard template and then loading Cu (as the nitrate salt) at different levels (3–9% by weight) by deposition-precipitation followed by calcination. The addition of TiO2 in MSP CeO2 revealed that the MSP CeO2 was significantly improved the oxygen vacancies of the catalyst by increasing the Ce3+ content from 38 to 75% and stabilizing the Ce3+ species by bonding with the oxygen as Ce(4f)-O(2p)-Ti(3d). Moreover, the bonding of MSP CeO2 with TiO2 generated the oxygen defect vacancies (s–Ti3+), allowing Cu2+ to occupy and be reduced to Cu+ during calcination. The smaller CeO2 crystallite size (2.7 nm) of 9Cu/CeO2–TiO2 increased the mass-specific CO-Oxidation, showing the best catalytic activity due to its highest redox properties, as determined by H2-TPR and also showing resistant property to water and carbon dioxide. Indeed, water was adsorbed on the Ce3+ sites, generating OHads which reacted with CO to form –COOH, resulting in CO2.

Rapid microwave-assisted hydrothermal synthesis of CeO2 octahedra with mixed valence states and their catalytic activity for thermal decomposition of ammonium perchlorate

2019 ◽  
Vol 6 (7) ◽  
pp. 1735-1743 ◽  
Author(s):  
Jing Shi ◽  
Huixiang Wang ◽  
Yequn Liu ◽  
Xiaobo Ren ◽  
Haizhen Sun ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Hydrothermal Synthesis ◽  
Ammonium Perchlorate ◽  
Oxygen Vacancies ◽  
Mixed Valence ◽  
High Concentration ◽  
Microwave Assisted ◽  
Valence States

CeO2 octahedra are prepared rapidly and they exhibit improved catalytic activity due to high concentration of oxygen vacancies and exposed (111) facets.

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