Nanocrystalline Doped Cerium Oxide as a Catalyst for SO2 Reduction by Co

1994 ◽  
Vol 344 ◽  
Author(s):  
Andreas Tschöpe ◽  
J. Y. Ying ◽  
W. Liu ◽  
M. Flytzani-Stephanopoulos
Keyword(s):  
Oxygen Vacancies ◽  
Elemental Sulfur ◽  
High Surface ◽  
High Surface Area ◽  
High Catalytic Activity ◽  
Metal Target ◽  
High Concentration ◽  
Gas Condensation ◽  
Structured Catalysts ◽  
La Doped

AbstractNanocrystalline processing by inert gas condensation has the inherent advantages of generating: (1) high surface area nanoclusters, (2) non-stoichiometric oxides, and (3) high dispersions of dopants. This approach is exploited in the synthesis of fluorite-structured catalysts for SO2 reduction by CO. Nanocrystalline CeO2-x, La-doped CeO2-x, and Cu-doped CeO2-x were produced by magnetron sputtering from a pure or mixed metal target, followed by controlled oxidation of the metallic clusters. The as-prepared doped and undoped nanocrystalline CeO2-x materials were found to be excellent catalysts for complete SO2 conversion to elemental sulfur. Undoped nanocrystalline CeO2-x enabled light-off at 460 °C, a temperature ∼120 °C lower than that over polycrystalline CeO2, which is a novel effective catalyst itself. The high catalytic activity of the nanocrystals was associated with their high concentration of oxygen vacancies. Excellent poisoning resistance was also exhibited by the nanocrystalline CeO2-x samples. These materials have stable activity in the presence of excess CO2.

scholarly journals Enhanced Activity for CO Preferential Oxidation over CuO Catalysts Supported on Nanosized CeO2 with High Surface Area and Defects

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 884
Author(s):  
Lei Gong ◽  
Weiwei Jie ◽  
Yumeng Liu ◽  
Xinchen Lin ◽  
Wenyong Deng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Oxygen Vacancies ◽  
High Surface ◽  
High Surface Area ◽  
High Catalytic Activity ◽  
Preferential Oxidation ◽  
Preferential Oxidation Of Co ◽  
Co Preferential Oxidation ◽  
Strength Of Interaction

Nanosizedceria (n-CeO2) was synthesized by a facile method in 2-methylimidazolesolution. The characterization results of XRD, N2 adsorption-desorption, Raman and TEM indicate that n-CeO2 shows a regular size of 10 ± 1 nm, a high surface area of 130 m2·g−1 and oxygen vacancies on the surface. A series of CuO/n-CeO2 catalysts (CuCeOX) with different copper loading were prepared for the preferential oxidation of CO in H2-rich gases (CO-PROX). All CuCeOX catalysts exhibit a high catalytic activity due to the excellent structural properties of n-CeO2, over which the 100% conversion of CO is obtained at 120 °C. The catalytic activity of CuCeOX catalysts increases in the order of CuCeO12 < CuCeO3 < CuCeO6 < CuCeO9. It is in good agreement with the order of the amount of active Cu+ species, Ce3+ species and oxygen vacancies on these catalysts, suggesting that the strength of interaction between highly dispersed CuO species and n-CeO2 is the decisive factor for the activity. The stronger interaction results in the formation of more readily reducible copper species on CuCeO9, which shows the highest activity with high stability and the broadest temperature “window” for complete CO conversion (120–180 °C).

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Flower-Shaped C-Dots/Co3O4{111} Constructed with Dual-Reaction Centers for Enhancement of Fenton-Like Reaction Activity and Peroxymonosulfate Conversion to Sulfate Radical

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 135
Author(s):  
Zhibin Wen ◽  
Qianqian Zhu ◽  
Jiali Zhou ◽  
Shudi Zhao ◽  
Jinnan Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Centers ◽  
Organic Radicals ◽  
The Other ◽  
High Catalytic Activity ◽  
High Adsorption ◽  
High Turnover

Novel flower-shaped C-dots/Co3O4{111} with dual-reaction centers were constructed to improve the Fenton-like reaction activity and peroxymonosulfate (PMS) conversion to sulfate radicals. Due to the exposure of a high surface area and Co3O4{111} facets, flower-shaped C-dots/Co3O4{111} could provide more Co(II) for PMS activation than traditional spherical Co3O4{110}. Meanwhile, PMS was preferred for adsorption on Co3O4{111} facets because of a high adsorption energy and thereby facilitated the electron transfer from Co(II) to PMS. More importantly, the Co–O–C linkage between C-dots and Co3O4{111} induced the formation of the dual-reaction center, which promoted the production of reactive organic radicals (R•). PMS could be directly reduced to SO4−• by R• over C-dots. On the other hand, electron transferred from R• to Co via Co–O–C linkage could accelerate the redox of Co(II)/(III), avoiding the invalid decomposition of PMS. Thus, C-dots doped on Co3O4{111} improved the PMS conversion rate to SO4−• over the single active site, resulting in high turnover numbers (TONs). In addition, TPR analysis indicated that the optimal content of C-dots doped on Co3O4{111} is 2.5%. More than 99% of antibiotics and dyes were degraded over C-dots/Co3O4{111} within 10 min. Even after six cycles, C-dots/Co3O4{111} still remained a high catalytic activity.

Coupling Ag-doping and rich oxygen vacancies in mesoporous NiCoO nanorods supported on nickel foam for highly efficient oxygen evolution

2017 ◽  
Vol 4 (11) ◽  
pp. 1783-1790 ◽  
Author(s):  
Kai-Li Yan ◽  
Jing-Qi Chi ◽  
Zi-Zhang Liu ◽  
Bin Dong ◽  
Shan-Shan Lu ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxygen Vacancies ◽  
Nickel Foam ◽  
High Surface ◽  
High Surface Area ◽  
Ag Doping ◽  
Highly Efficient

Ag-doped mesoporous NiCoO nanorods as efficient and stable electrocatalysts for oxygen evolution reaction have been synthesized with desirable conductivity, high surface area and rich oxygen vacancies.

scholarly journals Modern Trends in Design of Catalysts for Transformation of Biofuels into Syngas and Hydrogen: From Fundamental Bases to Performance in Real Feeds

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6334
Author(s):  
Vladislav Sadykov ◽  
Mikhail Simonov ◽  
Nikita Eremeev ◽  
Natalia Mezentseva
Keyword(s):  
Natural Gas ◽  
High Surface ◽  
High Surface Area ◽  
Internal Heat ◽  
Pilot Scale ◽  
Platinum Group Metals ◽  
Atomic Scale ◽  
Active Components ◽  
Structured Catalysts ◽  
Metal Support Interaction

This review considers problems related to design of efficient structured catalysts for natural gas and biofuels transformation into syngas. Their active components are comprised of fluorite, perovskite and spinel oxides or their nanocomposites (both bulk and supported on high surface area Mg-doped alumina or MgAl2O4) promoted by platinum group metals, nickel and their alloys. A complex of modern structural, spectroscopic and kinetic methods was applied to elucidate atomic-scale factors controlling their performance and stability to coking, such as dispersion of metals/alloys, strong metal-support interaction and oxygen mobility/reactivity as dependent upon their composition and synthesis procedures. Monolithic catalysts comprised of optimized active components loaded on structured substrates with a high thermal conductivity demonstrated high activity and stability to coking in processes of natural gas and biofuels reforming into syngas. A pilot-scale axial reactor equipped with the internal heat exchanger and such catalysts allowed to efficiently convert into syngas the mixture of natural gas, air and liquid biofuels in the autothermal reforming mode at low (~50–100 °C) inlet temperatures and GHSV up to 40,000 h−1.

High surface area, high catalytic activity titanium dioxide aerogels prepared by solvothermal crystallization

2020 ◽  
Vol 47 ◽  
pp. 223-230 ◽  
Author(s):  
Xian Yue ◽  
Junhui Xiang ◽  
Junyong Chen ◽  
Huaxin Li ◽  
Yunsheng Qiu ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
High Catalytic Activity

High-surface-area activated red mud supported Co3O4 catalysts for efficient catalytic oxidation of CO

RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94748-94755 ◽  
Author(s):  
Zhong-Pan Hu ◽  
Hui Zhao ◽  
Ze-Min Gao ◽  
Zhong-Yong Yuan
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Red Mud ◽  
High Surface ◽  
High Surface Area ◽  
High Catalytic Activity ◽  
Oxidation Of Co ◽  
Catalytic Oxidation Of Co ◽  
Low Temperature Co Oxidation

Red mud is activated and employed as the support of Co3O4 catalysts, exhibiting high catalytic activity for low-temperature CO oxidation.

Plasma-Engraved Co3 O4 Nanosheets with Oxygen Vacancies and High Surface Area for the Oxygen Evolution Reaction

2016 ◽  
Vol 128 (17) ◽  
pp. 5363-5367 ◽  
Author(s):  
Lei Xu ◽  
Qianqian Jiang ◽  
Zhaohui Xiao ◽  
Xingyue Li ◽  
Jia Huo ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxygen Vacancies ◽  
High Surface ◽  
High Surface Area

Synthesis and Hydrodesulfurization Performance of Bulk Ni-Mo-W Catalyst with High Surface Area

2013 ◽  
Vol 634-638 ◽  
pp. 604-607
Author(s):  
Hai Bin Yu ◽  
Jing Cheng Zhang ◽  
Jun Nan ◽  
Shan Geng ◽  
Yu Ting Zhang ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Great Influence ◽  
Precipitation Method ◽  
High Catalytic Activity ◽  
Organic Sulfur Compounds ◽  
Hydrodesulfurization Catalysts ◽  
Deep Desulfurization ◽  
Complex Organic

Bulk Ni-Mo-W hydrodesulfurization catalysts with high catalytic activity were synthesized via direct precipitation and controlled pH precipitation method, respectively. Analysis results shows that the preparation method has great influence on the morphology and pore structure, and further influence the hydrodesulfurization activity. The catalyst synthesized by controlled pH precipitation method has much higher surface area and pore volume, 132.9 m2/g and 0.30 mL/g, due to its developed porous structure accumulated by small crystal particles. The activity evaluation indicates that the bulk Ni-Mo-W hydrodesulfurization catalysts has good ultra-deep desulfurization activity of removing complex organic sulfur compounds, such as DBT and Cn-DBT.

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