Changes in the oxidation state of Pt single-atom catalysts upon removal of chloride ligands and their effect for electrochemical reactions

2019 ◽  
Vol 55 (45) ◽  
pp. 6389-6392 ◽  
Author(s):  
Sangyong Shin ◽  
Jiwhan Kim ◽  
Subin Park ◽  
Hee-Eun Kim ◽  
Yung-Eun Sung ◽  
...  
Keyword(s):  
Oxidation State ◽  
Single Atom ◽  
Electrochemical Reactions ◽  
Single Atoms ◽  
Chloride Ligands

The activity of Pt single-atom catalysts can be maximized by controlling the oxidation state of the single-atoms.

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

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

<p>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 (Fe<sup>3+</sup>), cobalt (Co<sup>3+</sup>), ruthenium (Ru<sup>3+</sup>), palladium (Pd<sup>2+</sup>), indium (In<sup>3+</sup>), iridium (Ir<sup>2+</sup>), and platinum (Pt<sup>2+</sup>) . As illustrated in Figure 1, the carbon surface can be tuned with different level of compositional complexities, including unary Pt<sub>1</sub>@NC, binary (MSAC-2, (PtFe)<sub>1</sub>@NC), ternary (MSAC-3, (PtFeIr)<sub>1</sub>@NC), quaternary (MSAC-4, (PtFeIrRu)<sub>1</sub>@NC), quinary (MSAC-5, (PtFeIrRuCo)<sub>1</sub>@NC), senary (MSAC-6, (PtFeIrRuCoPd)<sub>1</sub>@NC), and septenary (MSAC-7, (PtFeIrRuCoPdIn)<sub>1</sub>@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·mg<sub>metal</sub><sup>-1</sup> 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.</p>

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

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.

Synergy of Single Atoms Pd and Oxygen Vacancies on In2O3 for Highly Selective C1 Oxygenates Production from Methane under Visible Light

2021 ◽  
Author(s):  
Lei Luo ◽  
Lei Fu ◽  
Huifen Liu ◽  
Youxun Xu ◽  
Jialiang Xing ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Single Atom ◽  
Electron Transfer Pathway ◽  
Mild Conditions ◽  
Single Atoms ◽  
Primary Products ◽  
Critical Issues ◽  
Regulation Of Activity ◽  
Visible Irradiation ◽  
Dft Modelling

Abstract Methane (CH4) oxidation to high value chemicals under mild conditions through photocatalysis is a sustainable and appealing pathway, nevertheless confronting the critical issues on both conversion and selectivity. Herein, under visible irradiation (420 nm), the synergy of palladium (Pd) atom cocatalyst and oxygen vacancies (OVs) on In2O3 nanorods enabled superior photocatalytic CH4 activation by O2. The optimised catalyst reached ca. 100 µmol·h− 1 of C1 oxygenates, with a selectivity of primary products (CH3OH and CH3OOH) up to 82.5 %. Mechanism investigation elucidated that such superior photocatalysis was induced by the dedicated function of Pd single atoms and oxygen vacancies on boosting hole and electron transfer pathway, respectively. O2 was proven to be the only oxygen source for CH3OH production, while H2O acted as the promoter for efficient CH4 activation through ·OH production and facilitated product desorption as indicated by DFT modelling. This work thus provides new understandings on simultaneous regulation of activity and selectivity by the significant synergy of single atom cocatalysts and oxygen vacancies.

Dispersive Single‑Atom Metals Anchored on Functionalized Nanocarbons for Electrochemical Reactions

2019 ◽  
pp. 127-148
Author(s):  
Jin‑Cheng Li ◽  
Zidong Wei ◽  
Dong Liu ◽  
Dan Du ◽  
Yuehe Lin ◽  
...  
Keyword(s):  
Single Atom ◽  
Electrochemical Reactions

scholarly journals Interfacial-confined coordination to single-atom nanotherapeutics

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Limei Qin ◽  
Jie Gan ◽  
Dechao Niu ◽  
Yueqiang Cao ◽  
Xuezhi Duan ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Single Atom ◽  
Oxygen Species ◽  
High Quality ◽  
Efficient Energy ◽  
Coordination Strategy ◽  
Single Atoms ◽  
Highly Active ◽  
Narrow Bandgap ◽  
Catalytic Sites

AbstractPursuing and developing effective methodologies to construct highly active catalytic sites to maximize the atomic and energy efficiency by material engineering are attractive. Relative to the tremendous researches of carbon-based single atom systems, the construction of bio-applicable single atom materials is still in its infancy. Herein, we propose a facile and general interfacial-confined coordination strategy to construct high-quality single-atom nanotherapeutic agent with Fe single atoms being anchored on defective carbon dots confined in a biocompatible mesoporous silica nanoreactor. Furthermore, the efficient energy conversion capability of silica-based Fe single atoms system has been demonstrated on the basis of the exogenous physical photo irradiation and endogenous biochemical reactive oxygen species stimulus in the confined mesoporous network. More importantly, the highest photothermal conversion efficiency with the mechanism of increased electron density and narrow bandgap of this single atom structure in defective carbon was proposed by the theoretical DFT calculations. The present methodology provides a scientific paradigm to design and develop versatile single atom nanotherapeutics with adjustable metal components and tune the corresponding reactions for safe and efficient tumor therapeutic strategy.

Photoinduced Synergistic Catalysis on Zn Single-Atom-Loaded Hierarchical Porous Carbon for Highly Efficient CO2 Cycloaddition Conversion

2021 ◽  
Author(s):  
Lin Gong ◽  
Ji Sun ◽  
Yousong Liu ◽  
Guangcheng Yang
Keyword(s):  
Solar Energy ◽  
Porous Carbon ◽  
Single Atom ◽  
Hierarchical Porous Carbon ◽  
Reaction Conditions ◽  
Synergistic Catalysis ◽  
Single Atoms ◽  
Significant Challenge ◽  
Highly Efficient ◽  
Hierarchical Porous

The use of solar energy to drive efficient CO2 cycloaddition conversion under mild reaction conditions is highly desired but remains a significant challenge. In this communication, a Zn single-atoms-loaded N-doped...

Screening effective single-atom ORR and OER electrocatalysts from Pt decorated MXenes by first-principles calculations

2020 ◽  
Vol 8 (33) ◽  
pp. 17065-17077
Author(s):  
Dongxiao Kan ◽  
Ruqian Lian ◽  
Dashuai Wang ◽  
Xilin Zhang ◽  
Jing Xu ◽  
...  
Keyword(s):  
First Principles ◽  
Single Atom ◽  
First Principles Calculations ◽  
Single Atoms ◽  
Catalytic Performances

Pt single atoms doped on V-, Ti-, Nb-, and Cr-based MXenes presented high catalytic performances, especially the Nb- and Cr-based ones, which were promising bifunctional ORR/OER catalysts.

scholarly journals A pyrolysis-free path toward superiorly catalytic nitrogen-coordinated single atom

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw2322 ◽  
Author(s):  
Peng Peng ◽  
Lei Shi ◽  
Feng Huo ◽  
Chunxia Mi ◽  
Xiaohong Wu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Temperature ◽  
Oxygen Reduction ◽  
Structural Changes ◽  
Carbon Matrix ◽  
Single Atom ◽  
Synthetic Approach ◽  
Iron Phthalocyanine ◽  
Practical Applications ◽  
Single Atoms

Nitrogen-coordinated single-atom catalysts (SACs) have emerged as a frontier for electrocatalysis (such as oxygen reduction) with maximized atom utilization and highly catalytic activity. The precise design and operable synthesis of SACs are vital for practical applications but remain challenging because the commonly used high-temperature treatments always result in unpredictable structural changes and randomly created single atoms. Here, we develop a pyrolysis-free synthetic approach to prepare SACs with a high electrocatalytic activity using a fully π-conjugated iron phthalocyanine (FePc)–rich covalent organic framework (COF). Instead of randomly creating Fe-nitrogen moieties on a carbon matrix (Fe-N-C) through pyrolysis, we rivet the atomically well-designed Fe-N-C centers via intermolecular interactions between the COF network and the graphene matrix. The as-synthesized catalysts demonstrate exceptional kinetic current density in oxygen reduction catalysis (four times higher than the benchmark Pt/C) and superior power density and cycling stability in Zn-air batteries compared with Pt/C as air electrodes.

Metallic single-atoms confined in carbon nanomaterials for the electrocatalysis of oxygen reduction, oxygen evolution, and hydrogen evolution reactions

2020 ◽  
Vol 10 (19) ◽  
pp. 6420-6448 ◽  
Author(s):  
Mohd. Khalid ◽  
Prerna A. Bhardwaj ◽  
Ana M. B. Honorato ◽  
Hamilton Varela
Keyword(s):  
Oxygen Reduction ◽  
Hydrogen Evolution ◽  
Oxygen Evolution ◽  
Carbon Nanomaterials ◽  
Review Article ◽  
Single Atom ◽  
Single Atoms ◽  
Recent Advances ◽  
Hydrogen Evolution Reactions

Recent advances of single-atom-based carbon nanomaterials for the ORR, OER, HER, and bifunctional electrocatalysis are covered in this review article.

Z Dependence of Electron Scattering by Single Atoms into Annular Dark-Field Detectors

2011 ◽  
Vol 17 (6) ◽  
pp. 847-858 ◽  
Author(s):  
Michael M.J. Treacy
Keyword(s):  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Cross Section ◽  
Electron Scattering ◽  
Dark Field ◽  
Single Atom ◽  
Single Atoms ◽  
Annular Dark Field ◽  
Annular Detector ◽  
The Cross

AbstractA simple parameterization is presented for the elastic electron scattering cross sections from single atoms into the annular dark-field (ADF) detector of a scanning transmission electron microscope (STEM). The dependence on atomic number, Z, and inner reciprocal radius of the annular detector, q0, of the cross section σ(Z,q0) is expressed by the empirical relationwhere A(q0) is the cross section for hydrogen (Z = 1), and the detector is assumed to have a large outer reciprocal radius. Using electron elastic scattering factors determined from relativistic Hartree-Fock simulations of the atomic electron charge density, values of the exponent n(Z,q0) are tabulated as a function of Z and q0, for STEM probe sizes of 1.0 and 2.0 Å.Comparison with recently published experimental data for single-atom scattering [Krivanek et al. (2010). Nature464, 571–574] suggests that experimentally measured exponent values are systematically lower than the values predicted for elastic scattering from low-Z atoms. It is proposed that this discrepancy arises from the inelastic scattering contribution to the ADF signal. A simple expression is proposed that corrects the exponent n(Z,q0) for inelastic scattering into the annular detector.

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