scholarly journals What Changes on the Inverse Catalyst? Insight From CO Oxidation on Au-Supported Ceria Nanoparticles Using Ab Initio Molecular Dynamics

2019 ◽  
Author(s):  
Yong Li ◽  
Shikun Li ◽  
Marcus Bäumer ◽  
Lyudmila V. Moskaleva
Keyword(s):  
Ab Initio ◽  
Co Oxidation ◽  
Au Nanoparticles ◽  
Ab Initio Molecular Dynamics ◽  
Simulation Studies ◽  
Oxidation Reactions ◽  
Oxide Interfaces ◽  
Improved Stability ◽  
Reducible Oxides ◽  
Inverse Catalyst

Oxidation reactions catalyzed by Au nanoparticles supported on reducible oxides have been widely studied both experimentally and theoretically, whereas <i>inverse catalysts</i>, in which oxide nanoparticles are supported on metal surfaces, received considerably less attention. In both systems catalytic activity at metal – oxide interfaces can arise not only from each material contributing its functionality, but also from their interactions creating properties beyond the sum of individual components. Inverse catalysts may retain the synergy between the metal and oxide functionalities, while offering further specific advantages, e.g. a possibility to have better control over interfacial sites or to yield improved stability, activity, and selectivity. Our work provides the mechanism of O atom/vacancy diffusion-assisted Mars-van-Krevelen CO oxidation on gold-supported ceria nanoparticle through state-of-the-art ab initio molecular dynamic simulation studies.

scholarly journals What Changes on the Inverse Catalyst? Insight From CO Oxidation on Au-Supported Ceria Nanoparticles Using Ab Initio Molecular Dynamics

2019 ◽  
Author(s):  
Yong Li ◽  
Shikun Li ◽  
Marcus Bäumer ◽  
Lyudmila V. Moskaleva
Keyword(s):  
Ab Initio ◽  
Co Oxidation ◽  
Au Nanoparticles ◽  
Ab Initio Molecular Dynamics ◽  
Simulation Studies ◽  
Oxidation Reactions ◽  
Oxide Interfaces ◽  
Improved Stability ◽  
Reducible Oxides ◽  
Inverse Catalyst

Oxidation reactions catalyzed by Au nanoparticles supported on reducible oxides have been widely studied both experimentally and theoretically, whereas <i>inverse catalysts</i>, in which oxide nanoparticles are supported on metal surfaces, received considerably less attention. In both systems catalytic activity at metal – oxide interfaces can arise not only from each material contributing its functionality, but also from their interactions creating properties beyond the sum of individual components. Inverse catalysts may retain the synergy between the metal and oxide functionalities, while offering further specific advantages, e.g. a possibility to have better control over interfacial sites or to yield improved stability, activity, and selectivity. Our work provides the mechanism of O atom/vacancy diffusion-assisted Mars-van-Krevelen CO oxidation on gold-supported ceria nanoparticle through state-of-the-art ab initio molecular dynamic simulation studies.

What Changes on the Inverse Catalyst? Insights from CO Oxidation on Au-Supported Ceria Nanoparticles Using Ab Initio Molecular Dynamics

ACS Catalysis ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 3164-3174
Author(s):  
Yong Li ◽  
Shikun Li ◽  
Marcus Bäumer ◽  
Elena A. Ivanova-Shor ◽  
Lyudmila V. Moskaleva
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Co Oxidation ◽  
Ab Initio Molecular Dynamics ◽  
Ceria Nanoparticles ◽  
Inverse Catalyst

scholarly journals Size-dependent dynamic structures of supported gold nanoparticles in CO oxidation reaction condition

2018 ◽  
Vol 115 (30) ◽  
pp. 7700-7705 ◽  
Author(s):  
Yang He ◽  
Jin-Cheng Liu ◽  
Langli Luo ◽  
Yang-Gang Wang ◽  
Junfa Zhu ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Reaction ◽  
Au Nanoparticles ◽  
Working Condition ◽  
Ab Initio Molecular Dynamics ◽  
Present Observation ◽  
Size Dependent ◽  
Reaction Condition ◽  
Au Clusters ◽  
Co Oxidation Reaction

Gold (Au) catalysts exhibit a significant size effect, but its origin has been puzzling for a long time. It is generally believed that supported Au clusters are more or less rigid in working condition, which inevitably leads to the general speculation that the active sites are immobile. Here, by using atomic resolution in situ environmental transmission electron microscopy, we report size-dependent structure dynamics of single Au nanoparticles on ceria (CeO2) in CO oxidation reaction condition at room temperature. While large Au nanoparticles remain rigid in the catalytic working condition, ultrasmall Au clusters lose their intrinsic structures and become disordered, featuring vigorous structural rearrangements and formation of dynamic low-coordinated atoms on surface. Ab initio molecular-dynamics simulations reveal that the interaction between ultrasmall Au cluster and CO molecules leads to the dynamic structural responses, demonstrating that the shape of the catalytic particle under the working condition may totally differ from the shape under the static condition. The present observation provides insight on the origin of superior catalytic properties of ultrasmall gold clusters.

Combustion Driven by Fragment-based Ab Initio Molecular Dynamics Simulation

2019 ◽  
Author(s):  
Liqun Cao ◽  
Jinzhe Zeng ◽  
Mingyuan Xu ◽  
Chih-Hao Chin ◽  
Tong Zhu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Large Scale ◽  
Methane Combustion ◽  
Combustion Method ◽  
Dynamics Simulation ◽  
Ab Initio Molecular Dynamics ◽  
Computational Time ◽  
Combustion Mechanism ◽  
Daily Lives

Combustion is a kind of important reaction that affects people's daily lives and the development of aerospace. Exploring the reaction mechanism contributes to the understanding of combustion and the more efficient use of fuels. Ab initio quantum mechanical (QM) calculation is precise but limited by its computational time for large-scale systems. In order to carry out reactive molecular dynamics (MD) simulation for combustion accurately and quickly, we develop the MFCC-combustion method in this study, which calculates the interaction between atoms using QM method at the level of MN15/6-31G(d). Each molecule in systems is treated as a fragment, and when the distance between any two atoms in different molecules is greater than 3.5 Å, a new fragment involved two molecules is produced in order to consider the two-body interaction. The deviations of MFCC-combustion from full system calculations are within a few kcal/mol, and the result clearly shows that the calculated energies of the different systems using MFCC-combustion are close to converging after the distance thresholds are larger than 3.5 Å for the two-body QM interactions. The methane combustion was studied with the MFCC-combustion method to explore the combustion mechanism of the methane-oxygen system.

Tuning the Activities of Cu2O Nanostructures via the Oxide-Metal Interaction

2019 ◽  
Author(s):  
Wugen Huang ◽  
qingfei liu ◽  
Zhiwen Zhou ◽  
Yangsheng Li ◽  
Yong Wang ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Catalysis ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Oxidation Reactions ◽  
Tunneling Microscopy ◽  
Temperature Oxidation ◽  
Metal Interaction ◽  
Tremendous Importance ◽  
Oxygen Atoms

Despite tremendous importance in catalysis, the design and improvement of the oxide- metal interface has been hampered by the limited understanding on the nature of interfacial sites, as well as the oxide-metal interaction (OMI). Through the construction of well-defined Cu<sub>2</sub>O-Pt, Cu<sub>2</sub>O-Ag, Cu<sub>2</sub>O-Au interfaces, we found that Cu<sub>2</sub>O Nanostructures (NSs) on Pt exhibit much lower thermal stability than on Ag and Au, although they show the same surface and edge structures, as identified by element-specific scanning tunneling microscopy (ES-STM) images. The activities of the Cu<sub>2</sub>O-Pt and Cu<sub>2</sub>O-Au interfaces for CO oxidation were further compared at the atomic scale and showed in general that the interface with Cu<sub>2</sub>O NSs could annihilate the CO-poisoning problem suffered by Pt group metals and enhance the interaction with O<sub>2</sub>, which is a limiting step for CO oxidation catalysis on group IB metals. While both interfaces could react with CO at room temperature, the OMI was found to determine the reactivity of supported Cu<sub>2</sub>O NSs by 1) tuning the activity of interfacial oxygen atoms and 2) stabilizing oxygen vacancies or vice versa, the dissociated oxygen atoms at the interface. Our study provides new insight for OMI and for the development of Cu-based catalysts for low temperature oxidation reactions.

Tuning the Activities of Cu2O Nanostructures via the Oxide-Metal Interaction

2019 ◽  
Author(s):  
Wugen Huang ◽  
Yangsheng Li ◽  
Yong Wang ◽  
Yunchuan Tu ◽  
Dehui Deng ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Catalysis ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Oxidation Reactions ◽  
Tunneling Microscopy ◽  
Temperature Oxidation ◽  
Metal Interaction ◽  
Tremendous Importance ◽  
Oxygen Atoms

Despite tremendous importance in catalysis, the design and improvement of the oxide- metal interface has been hampered by the limited understanding on the nature of interfacial sites, as well as the oxide-metal interaction (OMI). Through the construction of well-defined Cu<sub>2</sub>O-Pt, Cu<sub>2</sub>O-Ag, Cu<sub>2</sub>O-Au interfaces, we found that Cu<sub>2</sub>O Nanostructures (NSs) on Pt exhibit much lower thermal stability than on Ag and Au, although they show the same surface and edge structures, as identified by element-specific scanning tunneling microscopy (ES-STM) images. The activities of the Cu<sub>2</sub>O-Pt and Cu<sub>2</sub>O-Au interfaces for CO oxidation were further compared at the atomic scale and showed in general that the interface with Cu<sub>2</sub>O NSs could annihilate the CO-poisoning problem suffered by Pt group metals and enhance the interaction with O<sub>2</sub>, which is a limiting step for CO oxidation catalysis on group IB metals. While both interfaces could react with CO at room temperature, the OMI was found to determine the reactivity of supported Cu<sub>2</sub>O NSs by 1) tuning the activity of interfacial oxygen atoms and 2) stabilizing oxygen vacancies or vice versa, the dissociated oxygen atoms at the interface. Our study provides new insight for OMI and for the development of Cu-based catalysts for low temperature oxidation reactions.

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