scholarly journals Alumina-supported sub-nanometer Pt10 clusters: amorphization and role of the support material in a highly active CO oxidation catalyst

2017 ◽  
Vol 5 (10) ◽  
pp. 4923-4931 ◽  
Author(s):  
Chunrong Yin ◽  
Fabio R. Negreiros ◽  
Giovanni Barcaro ◽  
Atsushi Beniya ◽  
Luca Sementa ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Catalyst ◽  
Support Material ◽  
Highly Active

Bridging the support gap in heterogeneous ultrananocatalysis.

Clay-based SiO2 as active support of gold nanoparticles for CO oxidation catalyst: Pivotal role of residual Al

2013 ◽  
Vol 35 ◽  
pp. 72-75 ◽  
Author(s):  
Yu Zhang ◽  
Bao Zhaorigetu ◽  
Meilin Jia ◽  
Chuncheng Chen ◽  
Jincai Zhao
Keyword(s):  
Gold Nanoparticles ◽  
Co Oxidation ◽  
Pivotal Role ◽  
Oxidation Catalyst ◽  
Residual Al

scholarly journals Preparation, Characterization and CO Oxidation Performance of Ag2O/γ-Al2O3 and (Ag2O+RuO2)/γ-Al2O3 Catalysts

Surfaces ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 251-264
Author(s):  
Antony Ananth ◽  
Rak Hyun Jeong ◽  
Jin-Hyo Boo
Keyword(s):  
Co Oxidation ◽  
Catalyst Support ◽  
Ruthenium Oxide ◽  
Catalytic Performance ◽  
Oxidation Catalyst ◽  
Pore Characteristics ◽  
Good Thermal Stability ◽  
Composite Catalysts ◽  
Highly Active ◽  
Temperature Programmed

This research dealt with the preparation and characterization of silver oxide (SLO) nanomaterials (NMs) and their composite catalysts (i.e., silver and ruthenium oxide (SLORUO)). The prepared materials were tested for their catalytic performance in carbon monoxide (CO) oxidation. Generally, silver in its pure state is not widely used for CO oxidation due to stability and structural issues. However, the usage of subsurface oxygen and oxygen-induced reconstruction could be effective as an oxidation catalyst at a slightly high temperature. The low-temperature reaction of highly active RuO2 (RUO) is a well-known phenomenon. Thus, the possibility of using it with SLO to observe the combined catalytic behavior was investigated. The wet chemically prepared SLO and SLORUO NMs exhibited spherical and rods in spherical aggregate-type surface morphology belonging to cubic and rutile crystalline structures, respectively. The NMs and catalysts (i.e., the NMs on γ-Al2O3 catalyst support at 0.5 and 1.0 wt.% ranges) showed good thermal stability. The dry and wet CO oxidation using RUO and SLO showed concentration-dependent catalytic activity. The RUO, SLO, and SLORUO composites using 0.5 wt.% showed full CO oxidation at 200, 300, and 225 °C, respectively. The reasons for the observed activity of the catalysts are explained based on the pore characteristics, chemical composition, and dispersion using H2 temperature-programmed reduction (TPR) behaviors.

Nanocast mesoporous MgAl2O4spinel monoliths as support for highly active gold CO oxidation catalyst

2006 ◽  
pp. 1772-1774 ◽  
Author(s):  
Wen-Cui Li ◽  
Massimiliano Comotti ◽  
An-Hui Lu ◽  
Ferdi Schüth
Keyword(s):  
Co Oxidation ◽  
Oxidation Catalyst ◽  
Highly Active

scholarly journals Facet-Dependent Reactivity of Ceria Nanoparticles Exemplified by CeO2-Based Transition Metal Catalysts: A Critical Review

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 452
Author(s):  
Michalis Konsolakis ◽  
Maria Lykaki
Keyword(s):  
Transition Metal ◽  
Co Oxidation ◽  
Critical Review ◽  
Rational Design ◽  
Metal Catalysts ◽  
Co2 Hydrogenation ◽  
Transition Metal Catalysts ◽  
Fine Tuning ◽  
Ceria Nanoparticles ◽  
Highly Active

The rational design and fabrication of highly-active and cost-efficient catalytic materials constitutes the main research pillar in catalysis field. In this context, the fine-tuning of size and shape at the nanometer scale can exert an intense impact not only on the inherent reactivity of catalyst’s counterparts but also on their interfacial interactions; it can also opening up new horizons for the development of highly active and robust materials. The present critical review, focusing mainly on our recent advances on the topic, aims to highlight the pivotal role of shape engineering in catalysis, exemplified by noble metal-free, CeO2-based transition metal catalysts (TMs/CeO2). The underlying mechanism of facet-dependent reactivity is initially discussed. The main implications of ceria nanoparticles’ shape engineering (rods, cubes, and polyhedra) in catalysis are next discussed, on the ground of some of the most pertinent heterogeneous reactions, such as CO2 hydrogenation, CO oxidation, and N2O decomposition. It is clearly revealed that shape functionalization can remarkably affect the intrinsic features and in turn the reactivity of ceria nanoparticles. More importantly, by combining ceria nanoparticles (CeO2 NPs) of specific architecture with various transition metals (e.g., Cu, Fe, Co, and Ni) remarkably active multifunctional composites can be obtained due mainly to the synergistic metalceria interactions. From the practical point of view, novel catalyst formulations with similar or even superior reactivity to that of noble metals can be obtained by co-adjusting the shape and composition of mixed oxides, such as Cu/ceria nanorods for CO oxidation and Ni/ceria nanorods for CO2 hydrogenation. The conclusions derived could provide the design principles of earth-abundant metal oxide catalysts for various real-life environmental and energy applications.

scholarly journals The role of JrPPOs in the browning of walnut explants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shugang Zhao ◽  
Hongxia Wang ◽  
Kai Liu ◽  
Linqing Li ◽  
Jinbing Yang ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Production Efficiency ◽  
Phenolic Content ◽  
Leaf Tissue ◽  
Limiting Factor ◽  
Mature Leaves ◽  
Survival Percentage ◽  
Highly Active ◽  
Young Leaves

Abstract Background Tissue culture is an effective method for the rapid breeding of seedlings and improving production efficiency, but explant browning is a key limiting factor of walnut tissue culture. Specifically, the polymerization of PPO-derived quinones that cause explant browning of walnut is not well understood. This study investigated explants of ‘Zanmei’ walnut shoot apices cultured in agar (A) or vermiculite (V) media, and the survival percentage, changes in phenolic content, POD and PPO activity, and JrPPO expression in explants were studied to determine the role of PPO in the browning of walnut explants. Results The results showed that the V media greatly reduced the death rate of explants, and 89.9 and 38.7% of the explants cultured in V media and A media survived, respectively. Compared with that of explants at 0 h, the PPO of explants cultured in A was highly active throughout the culture, but activity in those cultured in V remained low. The phenolic level of explants cultured in A increased significantly at 72 h but subsequently declined, and the content in the explants cultured in V increased to a high level only at 144 h. The POD in explants cultured in V showed high activity that did not cause browning. Gene expression assays showed that the expression of JrPPO1 was downregulated in explants cultured in both A and V. However, the expression of JrPPO2 was upregulated in explants cultured in A throughout the culture and upregulated in V at 144 h. JrPPO expression analyses in different tissues showed that JrPPO1 was highly expressed in stems, young leaves, mature leaves, catkins, pistils, and hulls, and JrPPO2 was highly expressed in mature leaves and pistils. Moreover, browning assays showed that both explants in A and leaf tissue exhibited high JrPPO2 activity. Conclusion The rapid increase in phenolic content caused the browning and death of explants. V media delayed the rapid accumulation of phenolic compounds in walnut explants in the short term, which significantly decreased explants mortality. The results suggest that JrPPO2 plays a key role in the oxidation of phenols in explants after branch injury.

scholarly journals A Mini Review on Doped Nickel-Based Electrocatalysts for Hydrogen Evolution Reaction

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4651
Author(s):  
Yilin Deng ◽  
Wei Lai ◽  
Bin Xu
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Water Electrolysis ◽  
Energy Resources ◽  
Alkaline Media ◽  
Hydrogen Energy ◽  
Heteroatom Doping ◽  
Highly Active ◽  
Production Of Hydrogen

The energy crisis and environmental pollution have attracted much attention and have promoted researches on clean and sustainable hydrogen energy resources. With the help of highly active and stable transition metal nickel-based catalysts, the production of hydrogen from water electrolysis from electrolyzed water has become an inexpensive and efficient strategy for generating hydrogen energy. In recent years, heteroatom doping has been found to be an effective strategy to improve the electrocatalytic hydrogen evolution reaction (HER) performances of nickel-based catalysts in acidic, neutral, and alkaline media. This review will highlight many recent works of inexpensive and readily available heteroatom-doped nickel-based HER catalysts. The evaluation methods for the performances of HER catalyst will be briefly described, and the role of heteroatom doping and its application in nickel-based catalyst will be summarized. This article will also point out some heteroatom doping strategies, which may provide references and inspire the design of other catalysts with dopants.

Redox chemistry of gold in a Au/FeO /CeO2 CO oxidation catalyst

2009 ◽  
Vol 10 (8) ◽  
pp. 1196-1202 ◽  
Author(s):  
A. Penkova ◽  
K. Chakarova ◽  
O.H. Laguna ◽  
K. Hadjiivanov ◽  
F. Romero Saria ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Redox Chemistry ◽  
Oxidation Catalyst

On the Role of Diffusion in the Oxidation of Fe, Ni, Co and the Fe-Sn Alloy by Calcium and Sodium Sulfates

2006 ◽  
Vol 258-260 ◽  
pp. 63-67
Author(s):  
V.M. Chumarev ◽  
V.P. Maryevich ◽  
V.A. Shashmurin
Keyword(s):  
Co Oxidation ◽  
Chemical Reaction ◽  
Diffusion Processes ◽  
Transport Processes ◽  
Diffusion Transport ◽  
Sodium Sulfates ◽  
Product Forms ◽  
Kinetics Of ◽  
Dominant Part

Diffusion processes play a dominant part in the macro kinetics of Fe, Ni and Co oxidation by calcium and sodium sulfates. Here, the reaction product forms a compact covering which spatially divides the reagents on the surface in the same way as in the oxidation and sulfidization of metals by oxygen and sulfur. Therefore, it is possible to assume in advance that interaction of metals with calcium and sodium sulfates will be determined not by the actual chemical reaction properly but by the diffusion transport processes.

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