In-situ E(S)TEM Observations of Single Atom Dynamics in Catalytic Reactions

Herein, we develop a non-selective charge compensation strategy to prepare multi-single-atom doped carbon (MSAC) in which a sodium p-toluenesulfonate (PTS-Na) doped polypyrrole (S-PPy) polymer is designed to anchor discretionary mixtures of multiple metal cations, including iron (Fe3+), cobalt (Co3+), ruthenium (Ru3+), palladium (Pd2+), indium (In3+), iridium (Ir2+), and platinum (Pt2+) . As illustrated in Figure 1, the carbon surface can be tuned with different level of compositional complexities, including unary Pt1@NC, binary (MSAC-2, (PtFe)1@NC), ternary (MSAC-3, (PtFeIr)1@NC), quaternary (MSAC-4, (PtFeIrRu)1@NC), quinary (MSAC-5, (PtFeIrRuCo)1@NC), senary (MSAC-6, (PtFeIrRuCoPd)1@NC), and septenary (MSAC-7, (PtFeIrRuCoPdIn)1@NC) samples. The structural evolution of carbon surface dictates the activities of both ORR and HER. The senary MSAC-6 achieves the ORR mass activity of 18.1 A·mgmetal-1 at 0.9 V (Vs reversible hydrogen electrode (RHE)) over 30K cycles, which is 164 times higher than that of commercial Pt/C. The quaternary MSAC-4 presented a comparable HER catalytic capability with that of Pt/C. These results indicate that the highly complexed carbon surface can enhance its ability over general electrochemical catalytic reactions. The mechanisms regarding of the ORR and HER activities of the alternated carbon surface are also theoretically and experimentally investigated in this work, showing that the synergistic effects amongst the co-doped atoms can activate or inactivate certain single-atom sites.

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The influence of chemical parameters on the in-situ metal carbonyl complex formation studied with the fast on-line reaction apparatus (FORA)

Radiochimica Acta ◽

10.1515/ract-2020-0031 ◽

2021 ◽

Vol 109 (4) ◽

pp. 243-260 ◽

Cited By ~ 1

Author(s):

Yves Wittwer ◽

Robert Eichler ◽

Dominik Herrmann ◽

Andreas Türler

Keyword(s):

Metal Carbonyl ◽

Ambient Air ◽

Single Atom ◽

Carbonyl Complex ◽

Carbonyl Complexes ◽

On Line ◽

Carrier Gases ◽

And Performance ◽

Atom Chemistry

Abstract A new setup named Fast On-line Reaction Apparatus (FORA) is presented which allows for the efficient investigation and optimization of metal carbonyl complex (MCC) formation reactions under various reaction conditions. The setup contains a 252Cf-source producing short-lived Mo, Tc, Ru and Rh isotopes at a rate of a few atoms per second by its 3% spontaneous fission decay branch. Those atoms are transformed within FORA in-situ into volatile metal carbonyl complexes (MCCs) by using CO-containing carrier gases. Here, the design, operation and performance of FORA is discussed, revealing it as a suitable setup for performing single-atom chemistry studies. The influence of various gas-additives, such as CO2, CH4, H2, Ar, O2, H2O and ambient air, on the formation and transport of MCCs was investigated. O2, H2O and air were found to harm the formation and transport of MCCs in FORA, with H2O being the most severe. An exception is Tc, for which about 130 ppmv of H2O caused an increased production and transport of volatile compounds. The other gas-additives were not influencing the formation and transport efficiency of MCCs. Using an older setup called Miss Piggy based on a similar working principle as FORA, it was additionally investigated if gas-additives are mostly affecting the formation or only the transport stability of MCCs. It was found that mostly formation is impacted, as MCCs appear to be much less sensitive to reacting with gas-additives in comparison to the bare Mo, Tc, Ru and Rh atoms.

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The electron-transfer intermediates of the oxygen evolution reaction (OER) as polarons by in situ spectroscopy

Physical Chemistry Chemical Physics ◽

10.1039/d1cp01760h ◽

2021 ◽

Author(s):

Hanna Lyle ◽

Suryansh Singh ◽

Michael Paolino ◽

Ilya Vinogradov ◽

Tanja Cuk

Keyword(s):

Electron Transfer ◽

Oxygen Evolution ◽

Oxygen Evolution Reaction ◽

Catalytic Reactions ◽

In Situ Spectroscopy ◽

Chemical Bonds

The conversion of diffusive forms of energy (electrical and light) into short, compact chemical bonds by catalytic reactions regularly involves moving a carrier from an environment that favors delocalization to one that favors localization.

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Active site engineering of atomically dispersed transition metal-heteroatom-carbon catalysts for oxygen reduction

Chemical Communications ◽

10.1039/d1cc03076k ◽

2021 ◽

Author(s):

Jiawei Zhu ◽

Shichun Mu

Keyword(s):

Transition Metal ◽

Oxygen Reduction ◽

Active Site ◽

Catalytic Reactions ◽

Single Atom ◽

Carbon Catalysts

Owing to the advantage of atomic utilization, the single-atom catalyst has attracted much attention and been employed in multifarious catalytic reactions. Their definite site configuration is favorable for exploring the...

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In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy

Nanoscale ◽

10.1039/c5nr05718c ◽

2015 ◽

Vol 7 (40) ◽

pp. 16952-16959 ◽

Cited By ~ 5

Author(s):

Kaige Zhang ◽

Gongke Li ◽

Yuling Hu

Keyword(s):

Raman Spectroscopy ◽

Surface Enhanced Raman Spectroscopy ◽

Catalytic Reactions ◽

Reaction Intermediates ◽

Reaction Conditions ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Nanocrystalline Magnesium Oxide ◽

Insight Into

The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water.

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57Fe Mössbauer Spectroscopic Study of the Geometrical Effects In the Catalytic Reactions with Intercalation Compounds

MRS Proceedings ◽

10.1557/proc-20-397 ◽

1982 ◽

Vol 20 ◽

Cited By ~ 2

Author(s):

P.P. Vaishnava ◽

P.A. Montano

Keyword(s):

Ferric Chloride ◽

Catalytic Reactions ◽

Fischer Tropsch ◽

Reaction Conditions ◽

Intercalated Graphite ◽

The Third ◽

Intercalated Compounds ◽

Catalytic Sites ◽

Geometrical Effects

ABSTRACTIn situ 57Fe Mössbauer spectra are reported for the first-, higher-stage ferric chloride, and a mixed ferric chloride-potassium chloride intercalated graphite catalysts under reduction and Fischer-Tropsch reaction conditions. The mass spectroscopic measurements reveal a different catalytic selectivity for the three catalysts. The first two catalysts predominantly possess a higher selectivity for methane, whereas the third catalyst has higher selectivity for the formation of propane. The differences are attributed to geometrical effects in the catalytic sites of the intercalated compounds.

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In Situ X-Ray Diffraction Analyses of Catalytic Reactions and Moderate-Pressure Geological Processes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.278-281.270 ◽

1998 ◽

Vol 278-281 ◽

pp. 270-277

Author(s):

T.B. Žunić ◽

G. Steffensen ◽

J. Villadsen

Keyword(s):

Catalytic Reactions ◽

Moderate Pressure ◽

X Ray Diffraction ◽

X Ray ◽

Geological Processes

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Iron-Imprinted Single-Atomic Site Catalyst-Based Nanoprobe for Detection of Hydrogen Peroxide in Living Cells

Nano-Micro Letters ◽

10.1007/s40820-021-00661-z ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Zhaoyuan Lyu ◽

Shichao Ding ◽

Maoyu Wang ◽

Xiaoqing Pan ◽

Zhenxing Feng ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Active Site ◽

Single Atom ◽

Site Structure ◽

Atomic Site ◽

Ion Imprinting ◽

Active Site Structure ◽

In Situ Detection ◽

Colorimetric Biosensing

AbstractFe-based single-atomic site catalysts (SASCs), with the natural metalloproteases-like active site structure, have attracted widespread attention in biocatalysis and biosensing. Precisely, controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs’ performance. In this work, we use a facile ion-imprinting method (IIM) to synthesize isolated Fe-N-C single-atomic site catalysts (IIM-Fe-SASC). With this method, the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites. The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references. Due to its excellent properties, IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide (H2O2). Using IIM-Fe-SASC as the nanoprobe, in situ detection of H2O2 generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity. This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H2O2 detection.

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