Ligand-coordinated Ir single-atom catalysts stabilized on oxide supports for ethylene hydrogenation and their evolution under a reductive atmosphere

Tunable Carbon Surface from Mono- to Multi-Metallic Single Atoms

10.26434/chemrxiv.12264083 ◽

2020 ◽

Author(s):

Weihong Lai ◽

Heng Wang ◽

Quan jiang ◽

Zichao Yan ◽

Hanwen Liu ◽

...

Keyword(s):

Synergistic Effects ◽

Structural Evolution ◽

Charge Compensation ◽

Catalytic Reactions ◽

Single Atom ◽

Carbon Surface ◽

Hydrogen Electrode ◽

Single Atoms ◽

Mass Activity ◽

Co Doped

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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Tunable Carbon Surface from Mono- to Multi-Metallic Single Atoms

10.26434/chemrxiv.12264083.v1 ◽

2020 ◽

Author(s):

Weihong Lai ◽

Heng Wang ◽

Quan jiang ◽

Zichao Yan ◽

Hanwen Liu ◽

...

Keyword(s):

Synergistic Effects ◽

Structural Evolution ◽

Charge Compensation ◽

Catalytic Reactions ◽

Single Atom ◽

Carbon Surface ◽

Hydrogen Electrode ◽

Single Atoms ◽

Mass Activity ◽

Co Doped

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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Atom-by-atom analysis of sintering dynamics and stability of Pt nanoparticle catalysts in chemical reactions

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0597 ◽

2020 ◽

Vol 378 (2186) ◽

pp. 20190597 ◽

Cited By ~ 1

Author(s):

Thomas E. Martin ◽

Robert W. Mitchell ◽

Edward D. Boyes ◽

Pratibha L. Gai

Keyword(s):

Critical Role ◽

Pt Nanoparticles ◽

Carbon Support ◽

Active Species ◽

Chemical Processes ◽

Single Atom ◽

Complex Nature ◽

Original Research ◽

Single Atoms

Supported Pt nanoparticles are used extensively in chemical processes, including for fuel cells, fuels, pollution control and hydrogenation reactions. Atomic-level deactivation mechanisms play a critical role in the loss of performance. In this original research paper, we introduce real-time in-situ visualization and quantitative analysis of dynamic atom-by-atom sintering and stability of model Pt nanoparticles on a carbon support, under controlled chemical reaction conditions of temperature and continuously flowing gas. We use a novel environmental scanning transmission electron microscope with single-atom resolution, to understand the mechanisms. Our results track the areal density of dynamic single atoms on the support between nanoparticles and attached to them; both as migrating species in performance degradation and as potential new independent active species. We demonstrate that the decay of smaller nanoparticles is initiated by a local lack of single atoms; while a post decay increase in single-atom density suggests anchoring sites on the substrate before aggregation to larger particles. The analyses reveal a relationship between the density and mobility of single atoms, particle sizes and their nature in the immediate neighbourhood. The results are combined with practical catalysts important in technological processes. The findings illustrate the complex nature of sintering and deactivation. They are used to generate new fundamental insights into nanoparticle sintering dynamics at the single-atom level, important in the development of efficient supported nanoparticle systems for improved chemical processes and novel single-atom catalysis. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function’.

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STRUCTURAL EVOLUTION OF EXCEPTIONALLY IRON-DEFICIENT HEMATITE NANOCRYSTALS AS OBSERVED BY IN SITU SYNCHROTRON X-RAY DIFFRACTION

10.1130/abs/2019am-337360 ◽

2019 ◽

Author(s):

Si Athena Chen ◽

◽

Peter Heaney ◽

Jeffrey E. Post ◽

Peter J. Eng ◽

...

Keyword(s):

Structural Evolution ◽

X Ray Diffraction ◽

X Ray ◽

Iron Deficient

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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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Improving peroxymonosulfate activation by copper ion-saturated adsorbent-based single atom catalysts for the degradation of organic contaminants: electron-transfer mechanism and the key role of Cu single atoms

Journal of Materials Chemistry A ◽

10.1039/d1ta02237g ◽

2021 ◽

Author(s):

Jingwen Pan ◽

Baoyu Gao ◽

Pijun Duan ◽

Kangying Guo ◽

Muhammad Akram ◽

...

Keyword(s):

Electron Transfer ◽

Organic Contaminants ◽

High Salinity ◽

Copper Ion ◽

Single Atom ◽

Electron Transfer Mechanism ◽

Persulfate Oxidation ◽

Single Atoms ◽

Oxidation Technology

Nonradical pathway-based persulfate oxidation technology is considered to be a promising method for high-salinity organic wastewater treatment.

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In situ synchrotron small- and wide-angle X-ray study on the structural evolution of Kevlar fiber under uniaxial stretching

RSC Advances ◽

10.1039/c6ra17671b ◽

2016 ◽

Vol 6 (85) ◽

pp. 81552-81558 ◽

Cited By ~ 7

Author(s):

Xiaoyun Li ◽

Feng Tian ◽

Ping Zhou ◽

Chunming Yang ◽

Xiuhong Li ◽

...

Keyword(s):

Structural Evolution ◽

Wide Angle ◽

Uniaxial Stretching ◽

X Ray ◽

Kevlar Fiber

In situ SAXS and WAXS study on the structural evolution and mechanism of two different Kevlar fibers during stretching.

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Structural evolution of NASICON-type Li1+xAlxGe2−x(PO4)3 using in situ synchrotron X-ray powder diffraction

Journal of Materials Chemistry A ◽

10.1039/c6ta00402d ◽

2016 ◽

Vol 4 (20) ◽

pp. 7718-7726 ◽

Cited By ~ 39

Author(s):

Dorsasadat Safanama ◽

Neeraj Sharma ◽

Rayavarapu Prasada Rao ◽

Helen E. A. Brand ◽

Stefan Adams

Keyword(s):

Solid Electrolyte ◽

Diffraction Study ◽

Powder Diffraction ◽

Structural Evolution ◽

X Ray Diffraction ◽

X Ray ◽

Nasicon Type ◽

Precursor Glass

In situ synchrotron X-ray diffraction study of the synthesis of solid-electrolyte Li1+xAlxGe2−x(PO4)3 (LAGP) from the precursor glass reveals that an initially crystallized dopant poor phase transforms into the Al-doped LAGP at 800 °C.

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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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In-situ X-ray tomographic imaging study of gas and structural evolution in a commercial Li-ion pouch cell

Journal of Power Sources ◽

10.1016/j.jpowsour.2021.230818 ◽

2022 ◽

Vol 520 ◽

pp. 230818

Author(s):

Wenjia Du ◽

Rhodri E. Owen ◽

Anmol Jnawali ◽

Tobias P. Neville ◽

Francesco Iacoviello ◽

...

Keyword(s):

Structural Evolution ◽

Imaging Study ◽

Tomographic Imaging ◽

X Ray ◽

Li Ion

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