The effect of cluster thickness on the adsorption of CH4 on Pdn

Zhang, Wenqin; Wang, Lichang

doi:10.1016/j.comptc.2010.10.027

Cited by 16 publications

(13 citation statements)

References 38 publications

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“…The homo- and heterolytic C–H bond cleavage (as well as functionalization) is well-known for its significance in chemistry and is regarded as a longstanding central challenge. − Metal cluster reactivity shows its own novelty in this topic. For example, considerable investigations have been conducted upon the activation of methane by gas-phase palladium model systems. − Experimental observations showed that neutral clusters Pd x ( x ≤ 24) tend to adsorb methane with a few exceptions (e.g., Pd 3 and Pd 4 ), while in contrast, the reactivity of small palladium oxides toward methane is size-dependent for methane dehydrogenation. , Recently, Bernhardt and co-workers showed an interesting study on the reactivity of methane with Pd x + ( x = 2–4) clusters. Mass spectrometric and reaction kinetic studies under different temperature conditions have elucidated the intrinsic propensity of palladium clusters in reacting with methane molecules, as depicted in Figure .…”

Section: Metal Cluster Reactivities With Nonpolar Moleculesmentioning

confidence: 99%

Reactivity of Metal Clusters

2016

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We summarize here the research advances on the reactivity of metal clusters. After a simple introduction of apparatuses used for gas-phase cluster reactions, we focus on the reactivity of metal clusters with various polar and nonpolar molecules in the gas phase and illustrate how elementary reactions of metal clusters proceed one-step at a time under a combination of geometric and electronic reorganization. The topics discussed in this study include chemical adsorption, addition reaction, cleavage of chemical bonds, etching effect, spin effect, the harpoon mechanism, and the complementary active sites (CAS) mechanism, among others. Insights into the reactivity of metal clusters not only facilitate a better understanding of the fundamentals in condensed-phase chemistry but also provide a way to dissect the stability and reactivity of monolayer-protected clusters synthesized via wet chemistry.

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Section: Metal Cluster Reactivities With Nonpolar Moleculesmentioning

confidence: 99%

Reactivity of Metal Clusters

2016

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“…In addition to the literature review, we assessed several categories of the DFT methods before eventually choosing the B3LYP hybrid GGA method for this study. Figure 4 shows the comparison between eight popular DFT methodsall coupled 3 RhH, 5 RhH, 2 RhC, 4 RhC, 2 RhO, 4 RhO, 1 Rh 2 , 3 Rh 2 , 5 Rh 2 , 1 RhCH 3 , 3 RhCH 3 , 5 RhCH 3 , 1 RhOH, 3 RhOH, and 5 RhOH, respectively. with the D3BJ empirical dispersionagainst the CCSD(T, full) benchmark calculations of the bond energies of small Rh species.…”

Section: ■ Computational Methodsmentioning

confidence: 99%

“…RhH, 5 RhH, 2 RhC, 4 RhC, 2 RhO, 4 RhO, 1 Rh 2 , 3 Rh 2 , 5 Rh 2 , 1 RhCH 3 , 3 RhCH 3 , 5 RhCH 3 , 1 RhOH, 3 RhOH, and 5 RhOH, were calculated. The numeric superscripts in front of these formulas are the spin multiplicities (M = 2S + 1), where S is the electron spin quantum number.…”

Section: Acs Omegamentioning

confidence: 99%

“…Approximately 134 million tons of ethene (ethylene) and 94 million tons of propene (propylene) were produced in 2014. , These numbers are expected to increase continuously as the consumption of ethene and propene is expected to increase continuously. Consequently, transition-metal (TM) catalysts used for the dehydrogenation of ethane and other light alkanes have been extensively studied both experimentally and theoretically. − The energy consumption for converting alkanes to alkenes is tremendous because it takes more than 400 kJ/mol of energy to break a C–H bond. Although the traditional vanadium oxide catalysts can reduce the energy barrier of the oxidative dehydrogenation (ODH) of alkanes to 100–200 kJ/mol, ,− a high-temperature environment is still required to provide enough thermal energy for this catalyzed reaction.…”

Section: Introductionmentioning

confidence: 99%

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Tools for Prescreening the Most Active Sites on Ir and Rh Clusters toward C–H Bond Cleavage of Ethane: NBO Charges and Wiberg Bond Indexes

Marquino

et al. 2019

ACS Omega

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B3LYP calculations were carried out to study the insertion of iridium (Ir) and rhodium (Rh) clusters into a C–H bond of ethane, which is often the rate-limiting step of the catalytic cycle of oxidative dehydrogenation of ethane. Our previous research on Ir catalysis correlates the diffusivity of the lowest unoccupied molecular orbital of the Ir clusters and the relative activities of the various catalytic sites. The drawback of this research is that the molecular orbital visualization is qualitative rather than quantitative. Therefore, in this study on C–H bond activation by the Ir and Rh clusters, we conducted analyses of natural bond orbital (NBO) charges and Wiberg bond indexes (WBIs), both of which are not only quantitative but also independent of the basis sets. We found strong correlation between the NBO charges, the WBIs, and the relative activities of the various catalytic sites on the Ir and Rh clusters. Analyses of the NBO charges and the WBIs provide a fast and reliable means of prescreening the most active sites on the Ir and Rh clusters and potentially on other similar transition-metal clusters that activate the C–H bonds of ethane and other light alkanes.

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“…However, certain small hydrocarbons such as benzene can have their binding energies overestimated [ 209 ]. While the relative energy changes for different systems vary from none impact to significant for the purpose of rational design of new materials, good DFT methods that can describe accurately the vdW interactions are needed [ 113 , 224 ].…”

Section: Application Of Quantum Computation In the Study Of Dye Agmentioning

confidence: 99%

Cause, Regulation and Utilization of Dye Aggregation in Dye-Sensitized Solar Cells

Testoff

Wang

2020

Molecules

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As an important member of third generation solar cell, dye-sensitized solar cells (DSSCs) have the advantages of being low cost, having an easy fabrication process, utilizing rich raw materials and a high-power conversion efficiency (PCE), prompting nearly three decades as a research hotspot. Recently, increasing the photoelectric conversion efficiency of DSSCs has proven troublesome. Sensitizers, as the most important part, are no longer limited to molecular engineering, and the regulation of dye aggregation has become a widely held concern, especially in liquid DSSCs. This review first presents the operational mechanism of liquid and solid-state dye-sensitized solar cells, including the influencing factors of various parameters on device efficiency. Secondly, the mechanism of dye aggregation was explained by molecular exciton theory, and the influence of various factors on dye aggregation was summarized. We focused on a review of several methods for regulating dye aggregation in liquid and solid-state dye-sensitized solar cells, and the advantages and disadvantages of these methods were analyzed. In addition, the important application of quantum computational chemistry in the study of dye aggregation was introduced. Finally, an outlook was proposed that utilizing the advantages of dye aggregation by combining molecular engineering with dye aggregation regulation is a research direction to improve the performance of liquid DSSCs in the future. For solid-state dye-sensitized solar cells (ssDSSCs), the effects of solid electrolytes also need to be taken into account.

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The effect of cluster thickness on the adsorption of CH4 on Pdn

Cited by 16 publications

References 38 publications

Reactivity of Metal Clusters

Reactivity of Metal Clusters

Tools for Prescreening the Most Active Sites on Ir and Rh Clusters toward C–H Bond Cleavage of Ethane: NBO Charges and Wiberg Bond Indexes

Cause, Regulation and Utilization of Dye Aggregation in Dye-Sensitized Solar Cells

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