Ba-Addition Induced Enhanced Surface Reducibility of SrTiO3: Implication on Catalytic Aspects

2019 ◽  
Author(s):  
Noopur Jain ◽  
ahin roy ◽  
Angana De
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Oxygen Vacancies ◽  
Cation Substitution ◽  
Surface Oxygen ◽  
Chemical States ◽  
A Site ◽  
Adsorption Desorption ◽  
Enhanced Surface

This work compares the capacity of generating the surface oxygen vacancies over SrTiO<sub>3</sub>, BaTiO<sub>3</sub> and the mixed Sr<sub>0.5</sub>Ba<sub>0.5</sub>TiO<sub>3</sub>. This aspect is elucidated by significantly different chemical states of the elements on the surface of the three materials. Along with the fundamental materials aspect, CO oxidation studies complement the highest surface reducibility of the Sr<sub>0.5</sub>Ba<sub>0.5</sub>TiO<sub>3</sub> catalyst. With detailed adsorption-desorption studies, we report that the A-site cation substitution renders a better surface-reducibility induced catalytic activity for CO oxidation.

Ba-Addition Induced Enhanced Surface Reducibility of SrTiO3: Implication on Catalytic Aspects

2019 ◽  
Author(s):  
Noopur Jain ◽  
ahin roy ◽  
Angana De
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Oxygen Vacancies ◽  
Cation Substitution ◽  
Surface Oxygen ◽  
Chemical States ◽  
A Site ◽  
Adsorption Desorption ◽  
Enhanced Surface

This work compares the capacity of generating the surface oxygen vacancies over SrTiO<sub>3</sub>, BaTiO<sub>3</sub> and the mixed Sr<sub>0.5</sub>Ba<sub>0.5</sub>TiO<sub>3</sub>. This aspect is elucidated by significantly different chemical states of the elements on the surface of the three materials. Along with the fundamental materials aspect, CO oxidation studies complement the highest surface reducibility of the Sr<sub>0.5</sub>Ba<sub>0.5</sub>TiO<sub>3</sub> catalyst. With detailed adsorption-desorption studies, we report that the A-site cation substitution renders a better surface-reducibility induced catalytic activity for CO oxidation.

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.

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.

Surface oxygen vacancies in gold based catalysts for CO oxidation

RSC Advances ◽  
2014 ◽  
Vol 4 (25) ◽  
pp. 13145-13152 ◽  
Author(s):  
F. Romero-Sarria ◽  
J. J. Plata ◽  
O. H. Laguna ◽  
A. M. Márquez ◽  
M. A. Centeno ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxygen Vacancies ◽  
Surface Oxygen

The Different Morphology of Co3O4 Catalysts and Application in the Abatement of Carbon Monoxide

2021 ◽  
Vol 21 (12) ◽  
pp. 6082-6087
Author(s):  
Chih-Wei Tang ◽  
Hsiang-Yu Shih ◽  
Ruei-Ci Wu ◽  
Chih-Chia Wang ◽  
Chen-Bin Wang
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.

Influence of surface oxygen vacancies on the catalytic activity of copper oxide

1992 ◽  
Vol 75 (3) ◽  
pp. 277-291 ◽  
Author(s):  
Andries Q.M. Boon ◽  
Fancine van Looij ◽  
John W. Geus
Keyword(s):  
Catalytic Activity ◽  
Copper Oxide ◽  
Oxygen Vacancies ◽  
Surface Oxygen
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