Boosting CO2-to-CO conversion on a robust single-atom copper decorated carbon catalyst by enhancing intermediate binding strength

2021 ◽  
Author(s):  
Shixia Chen ◽  
Yuewei Li ◽  
Zhuogang Bu ◽  
Fangqi Yang ◽  
Junhui Luo ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Energy Barrier ◽  
Single Atom ◽  
Carbon Catalyst ◽  
Binding Strength ◽  
Co Conversion

The hydrogen-bond strengthen the *COOH adsorption and lower the CO2(g)→*COOH energy barrier on Cu–N–C electrocatalyst, simultaneously yielding a high CO FE and TOF.

scholarly journals Insights on forming N,O-coordinated Cu single-atom catalysts for electrochemical reduction CO2 to methane

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanming Cai ◽  
Jiaju Fu ◽  
Yang Zhou ◽  
Yu-Chung Chang ◽  
Qianhao Min ◽  
...  
Keyword(s):  
Energy Barrier ◽  
Active Sites ◽  
Theoretical Calculations ◽  
High Energy ◽  
Single Atom ◽  
Faradaic Efficiency ◽  
High Energy Barrier ◽  
Catalytic Sites ◽  
Electron Reduction ◽  
First Time

AbstractSingle-atom catalysts (SACs) are promising candidates to catalyze electrochemical CO2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN2O2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO2 to CH4 with current density of 40 mA·cm-2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN2O2 active sites are due to the proper elevated CH4 and H2 energy barrier and fine-tuned electronic structure of Cu active sites.

scholarly journals Interplay between spin crossover and proton migration along short strong hydrogen bonds

2021 ◽  
Author(s):  
Verónica Jornet-Mollá ◽  
Carlos Giménez-Saiz ◽  
Laura Cañadillas-Delgado ◽  
Dmitry S. Yufit ◽  
Judith A. K. Howard ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Low Temperatures ◽  
Energy Barrier ◽  
Spin Crossover ◽  
Strong Hydrogen Bond ◽  
Activation Energy Barrier ◽  
Proton Migration

A proton migration across a short strong hydrogen bond can be triggered by spin crossover of a remote Fe2+ cation, with the onset of a photoinduced activation energy barrier for proton motion at low temperatures.

NORMAL GRAIN GROWTH IN ZONE-REFINED HIGH-PURITY METALS

1959 ◽  
Vol 37 (4) ◽  
pp. 496-498 ◽  
Author(s):  
E. L. Holmes ◽  
W. C. Winegard
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
High Purity ◽  
Liquid State ◽  
Energy Barrier ◽  
Boundary Migration ◽  
Single Atom ◽  
Grain Boundary Migration

Comparisons are made between theoretical and experimental rates of boundary migration during grain growth in zone-refined metals; these indicate that a single-atom process is involved. A model is proposed for the mechanism of grain-boundary migration based on the assumption of a single-atom process and the fact that the energies of activation for grain growth, both in zone-refined lead and tin, are similar to the energy barrier to be overcome by an atom in transferring from the solid to the liquid state during melting.

A Learning Method for Predicting the Binding Strength in RNA-Protein Complexes

2014 ◽  
Vol 644-650 ◽  
pp. 5291-5294
Author(s):  
Tong Wang ◽  
Jian Xin Xue ◽  
Tian Xia
Keyword(s):  
Hydrogen Bond ◽  
Protein Binding ◽  
Rna Binding ◽  
Protein Complexes ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Protein Binding Sites ◽  
Binding Strength ◽  
Rna Protein Complexes ◽  
Score Matrix

Hydrogen bond and van der Waals interactions between protein and RNA are important. We have developed a set of algorithms for predicting RNA-Protein binding strength by analyzing hydrogen bond and van der Waals interactions between protein and RNA. Firstly, we must identify the RNA-Protein binding sites. In this study, we use features including Pseudo Position-Specific Score Matrix (PsePSSM) computed by PSI-BLAST and Dipeptide Composition (DC) as feature vectors. Then, the classifier is employed to identify the residues that interact with RNA in RNA-binding protein. Then, take into account the number of amino acids hydrogen bonding and van der Waals forces to any nucleotide, the binding strength is calculated. Finally, fuzzy sets method is adopted to predict the binding strength is strong or weak. Our experiments show that the above methods are used effectively to deal with this complicated problem of predicting RNA-protein binding strength.

scholarly journals Tuning the coordination number of Fe single atoms for the efficient reduction of CO2

2020 ◽  
Vol 22 (21) ◽  
pp. 7529-7536
Author(s):  
Huihuang Chen ◽  
Xu Guo ◽  
Xiangdong Kong ◽  
Yulin Xing ◽  
Yan Liu ◽  
...  
Keyword(s):  
Coordination Number ◽  
Single Atom ◽  
Single Atoms ◽  
Electrocatalytic Performance ◽  
Efficient Reduction ◽  
Co Conversion ◽  
Reduction Of Co2

The coordination number of Fe single-atom catalysts (Fe–N5/Fe–N6) significantly affects the electrocatalytic performance during CO2-to-CO conversion.

A novel single-atom catalyst for CO oxidation in humid environmental conditions: Ni-embedded divacancy graphene

2020 ◽  
Vol 8 (1) ◽  
pp. 287-295 ◽  
Author(s):  
Quanguo Jiang ◽  
Jianfeng Zhang ◽  
Huajie Huang ◽  
Yuping Wu ◽  
Zhimin Ao
Keyword(s):  
Co Oxidation ◽  
Environmental Conditions ◽  
Energy Barrier ◽  
Single Atom ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

A termolecular Eley–Rideal (TER) mechanism is preferred for CO oxidation on Ni-DG in humid environments, and the energy barrier for the rate limiting step (2CO + O2 → OCOOCO) is only 0.34 eV.

THERMAL DIFFUSION DYNAMIC BEHAVIOR OF TWO-DIMENSIONAL Ag-SMALL CLUSTERS ON Ag(1 1 1) SURFACE

2015 ◽  
Vol 22 (05) ◽  
pp. 1550067 ◽  
Author(s):  
ZAKIRUR-REHMAN ◽  
SARDAR SIKANDAR HAYAT
Keyword(s):  
Diffusion Coefficient ◽  
Ab Initio ◽  
Thermal Diffusion ◽  
Energy Barrier ◽  
Density Functional ◽  
Kinetic Monte Carlo ◽  
Md Simulations ◽  
Single Atom ◽  
Two Dimensional ◽  
Effective Energy

In this paper, the thermal diffusion behavior of small two-dimensional Ag -islands on Ag (1 1 1) surface has been explored using molecular dynamics (MD) simulations. The approach is based on semi-empirical potentials. The key microscopic processes responsible for the diffusion of Ag 1−5 adislands on Ag (1 1 1) surface are identified. The hopping and zigzag concerted motion along with rotation are observed for Ag one-atom to three-atom islands while single-atom and multi-atom processes are revealed for Ag four-atom and five-atom islands, during the diffusion on Ag (1 1 1) surface. The same increasing/decreasing trend in the diffusion coefficient and effective energy barrier is observed in both the self learning kinetic Monte Carlo (SLKMC) and MD calculations, for the temperature range of 300–700 K. An increase in the value of effective energy barrier is noticed with corresponding increase in the number of atoms in Ag -adislands. A reasonable linear fit is observed for the diffusion coefficient for studied temperatures (300, 500 and 700 K). For the observed diffusion mechanisms, our findings are in good agreement with ab initio density-functional theory (DFT) calculations for Al / Al (1 1 1) while the energy barrier values are in same range as the experimental values for Cu / Ag (1 1 1) and the theoretical values using ab initio DFT supplemented with embedded-atom method for Ag / Ag (1 1 1).

scholarly journals Electronic regulation of Ni single atom by confined Ni nanoparticles for fast and energy-efficient CO2 electroreduction

2021 ◽  
Author(s):  
Wenhao Ren ◽  
Xin Tan ◽  
Chen Jia ◽  
Anna Krammer ◽  
Qian Sun ◽  
...  
Keyword(s):  
Active Sites ◽  
Cell Voltage ◽  
Single Atom ◽  
Ni Nanoparticles ◽  
Precious Metal Catalysts ◽  
Co Conversion ◽  
Co2 Electroreduction ◽  
Enhanced Adsorption ◽  
Direct Solid ◽  
Nanoparticle Catalyst

Abstract Electrocatalytic CO2 to CO conversion is approaching the industrial benchmark. Currently, Au electrodes show the best performance, whereas non-precious metal catalysts exhibit inferior activity. Here we show a densely populated Ni single-atom on nanoparticle catalyst (NiSA/NP) via direct solid-sate pyrolysis, where Ni nanoparticles donate electrons to Ni(i)-N-C sites via carbon nanotubes network, achieves a high CO current of 352 mA cm− 2 at -0.55 V vs RHE in an alkaline flow cell. When coupled with a NiFe-based oxygen evolution anode into a zero-gap membrane electrolyser, it delivers an industrial-relevant CO current of 310 mA cm− 2 at a low cell voltage of -2.3 V, corresponding to an overall energy efficiency of 57%. The superior CO2 electroreduction performance is attributed to the enhanced adsorption of key intermediate COOH* on electron-rich Ni single atom, together with the dense active sites.

MnOx Enhanced Atomically Dispersed Iron-Nitrogen-Carbon Catalyst for Oxygen Reduction Reaction

2021 ◽  
Author(s):  
Shichao Ding ◽  
Zhaoyuan Lyu ◽  
Erik Sarnello ◽  
Mingjie Xu ◽  
Lingzhe Fang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Proton Exchange Membrane ◽  
Cost Effective ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Single Atom ◽  
Carbon Catalyst ◽  
Highly Efficient ◽  
Exchange Membrane

Cost-effective and highly efficient Fe-N‑C single-atom catalysts (SACs) have been known as the most promising potential Pt substitutes for the cathodic oxygen reduction reaction (ORR) in proton exchange membrane fuel...

THEORETICAL INVESTIGATIONS ON THE MECHANISM OF ACTIVATION OF AMMONIA BY A p-DIMETHYLAMINOPYRIDINE COORDINATED SI=O DOUBLE BOND

2012 ◽  
Vol 11 (02) ◽  
pp. 437-481 ◽  
Author(s):  
YUN-QING HE ◽  
ZE-QIN CHEN ◽  
YING XUE
Keyword(s):  
Hydrogen Bond ◽  
Free Energy ◽  
Energy Barrier ◽  
Intermolecular Hydrogen Bond ◽  
Free Energy Barrier ◽  
Theoretical Investigations ◽  
Unique Pair ◽  
First Time ◽  
Good Interpretation ◽  
Good Agreement

Recently, Xiong et al. reported an activation of ammonia by p-dimethylaminopyridine (DMAP) coordinated silanone (DMAP→Si(L)=O, DS) affording a unique pair of sila-hemiaminal (SH) and silanoic amide (SA) tautomers (Xiong Y, Yao S, Müller R, Kaupp M, Driess M, J Am Chem Soc132:6912, 2010). In this paper, the mechanisms of the activation of ammonia affording SH and SA, the successive generation of hydrogen bonded complex pair SH–SA and the tautomerization between SH and SA have been intensively investigated computationally for the first time at MP2/6-311+G(2d,p)//B3LYP/6-31+G(d,p) level in toluene. The concerted Paths C and D with ammonia assistance are determined by our calculations to be the dominant pathways corresponding to forming SH and SA from DS, respectively. The free energy barrier of Path C affording SH from DS is 14.45 kcal/mol, and that of Path D affording SA is 21.46 kcal/mol. So it is determined theoretically that Path C is dynamically dominant over Path D. And the pair SH–SA is formed then spontaneously by intermolecular hydrogen bond (O–H ⋯ O′) without any barrier. While the tautomerization between SH and SA is nonsignficant resulting from the corresponding relative high barriers (23.79 kcal/mol for process from SH to SA and 26.52 kcal/mol for process from SA to SH). Our results are in good agreement with and good interpretation of the experimental results by Xiong et al.

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