scholarly journals Can NOx reduction by CO react over carbon-based single-atom catalysts at low temperatures? A theoretical study

2021 ◽  
Author(s):  
Jie Shi ◽  
Wei Zhang ◽  
Yuan Pu ◽  
Hui Li ◽  
Dan Wang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Rational Design ◽  
Nox Reduction ◽  
Group Iv ◽  
Single Atom ◽  
Catalytic Activities ◽  
Doped Graphene ◽  
Group Iv Elements ◽  
Good Descriptor ◽  
Carbon Based

First principles studies combined with the microkinetic analysis were performed to study the reliability and reaction mechanisms of single-atom doped graphene (SADGr) materials in catalyzing NOx reduction with CO. By screening the 3d transition metals (Sc-Zn) and group-IV elements (Si and Ge), it was found that the Ti and Co doped graphene sheets (TiGr and CoGr) respectively own excellent catalytic activities in the NO/NO2-to-N2O and the N2O-to-N2 processes at low temperatures. Therefore, the TiGr/CoGr composite can be a promising catalyst in NOx reduction with CO. It was further revealed the combination of adsorption energy and electronegativity was a good descriptor to predict the activation energies. The obtained results can provide useful information for rational design of carbon-based single-atom catalysts for NOx reduction by CO at low temperatures.

Spins, Phonons, and Hardness

1995 ◽  
Vol 410 ◽  
Author(s):  
John J. Gilman
Keyword(s):  
Debye Temperature ◽  
Acoustic Waves ◽  
Low Temperatures ◽  
Group Iv ◽  
Dislocation Mobility ◽  
Spin Pair ◽  
Pair Bonds ◽  
Debye Temperatures ◽  
Einstein Temperature ◽  
Group Iv Elements

ABSTRACTIn crystals (and/or glasses) with localized sp3 or spd-bonding orbitals, dislocations have very low mobilities, making the crystals very hard. Classical Peierls-Nabarro theory does not account for the low mobility. The breaking of spin-pair bonds which creates internal free-radicals must be considered. Therefore, a theory based on quantum mechanics has been proposed (Science, 261, 1436 (1993)). It has been applied successfully to diamond, Si, Ge, SiC, and with a modification to TiC and WC. It has recently been extended to account for the temperature independence of the hardness of silicon at low temperatures together with strong softening at temperatures above the Debye temperature. It is quantitatively consistent with the behaviors of the Group IV elements (C, Si, Ge, Sn) when their Debye temperatures are used as normalizing factors; and appears to be consistent with data for TiC if an Einstein temperature for carbon is used. Since the Debye temperature marks the approximate point at which phonons of atomic wavelengths become excited (as contrasted with collective acoustic waves), this confirms the idea that the process which limits dislocation mobility is localized to atomic dimensions (sharp kinks).

scholarly journals Dipole Field Interactions Determine the CO2 Reduction Activity of 2D FeNC Single Atom Catalysts

2020 ◽  
Author(s):  
Sudarshan Vijay ◽  
Joseph Gauthier ◽  
Hendrik Heenen ◽  
Vanessa Jane Bukas ◽  
Henrik Høgh Kristoffersen ◽  
...  
Keyword(s):  
Rational Design ◽  
Design Principle ◽  
Ph Dependence ◽  
Co2 Reduction ◽  
Catalyst Design ◽  
Single Atom ◽  
Reduction Activity ◽  
Electrochemical Co2 Reduction ◽  
Doped Graphene ◽  
Fuels And Chemicals

<p>Electrochemical CO2 Reduction (CO2R) can potentially allow for the sustainable production of valuable fuels and chemicals. Recently, single atom catalysts on a 2D support have been shown to be a promising catalyst candidate. Using state-of-the-art methods, we develop a model for Fe doped graphene which rationalises several critical experimental observations: the contentious origin of the pH dependence of reactivity and the dependence of current-potential relationships on active site. We show that single atom catalysts have the unique ability to stabilise different dipoles associated with critical reaction intermediates, which translates to significant shifts in activity. This provides a new rational design principle and paves the way for rigorous computation-guided catalyst design of new single atom catalysts for CO2R.</p>

scholarly journals Dipole Field Interactions Determine the CO2 Reduction Activity of 2D FeNC Single Atom Catalysts

2020 ◽  
Author(s):  
Sudarshan Vijay ◽  
Joseph Gauthier ◽  
Hendrik Heenen ◽  
Vanessa Jane Bukas ◽  
Henrik Høgh Kristoffersen ◽  
...  
Keyword(s):  
Rational Design ◽  
Design Principle ◽  
Ph Dependence ◽  
Co2 Reduction ◽  
Catalyst Design ◽  
Single Atom ◽  
Reduction Activity ◽  
Electrochemical Co2 Reduction ◽  
Doped Graphene ◽  
Fuels And Chemicals

<p>Electrochemical CO2 Reduction (CO2R) can potentially allow for the sustainable production of valuable fuels and chemicals. Recently, single atom catalysts on a 2D support have been shown to be a promising catalyst candidate. Using state-of-the-art methods, we develop a model for Fe doped graphene which rationalises several critical experimental observations: the contentious origin of the pH dependence of reactivity and the dependence of current-potential relationships on active site. We show that single atom catalysts have the unique ability to stabilise different dipoles associated with critical reaction intermediates, which translates to significant shifts in activity. This provides a new rational design principle and paves the way for rigorous computation-guided catalyst design of new single atom catalysts for CO2R.</p>

scholarly journals Dipole Field Interactions Determine the CO2 Reduction Activity of 2D FeNC Single Atom Catalysts

2020 ◽  
Author(s):  
Sudarshan Vijay ◽  
Joseph Gauthier ◽  
Hendrik Heenen ◽  
Vanessa Jane Bukas ◽  
Henrik Høgh Kristoffersen ◽  
...  
Keyword(s):  
Rational Design ◽  
Design Principle ◽  
Ph Dependence ◽  
Co2 Reduction ◽  
Catalyst Design ◽  
Single Atom ◽  
Reduction Activity ◽  
Electrochemical Co2 Reduction ◽  
Doped Graphene ◽  
Fuels And Chemicals

<p>Electrochemical CO2 Reduction (CO2R) can potentially allow for the sustainable production of valuable fuels and chemicals. Recently, single atom catalysts on a 2D support have been shown to be a promising catalyst candidate. Using state-of-the-art methods, we develop a model for Fe doped graphene which rationalises several critical experimental observations: the contentious origin of the pH dependence of reactivity and the dependence of current-potential relationships on active site. We show that single atom catalysts have the unique ability to stabilise different dipoles associated with critical reaction intermediates, which translates to significant shifts in activity. This provides a new rational design principle and paves the way for rigorous computation-guided catalyst design of new single atom catalysts for CO2R.</p>

scholarly journals O-coordinated W-Mo dual-atom catalyst for pH-universal electrocatalytic hydrogen evolution

2020 ◽  
Vol 6 (23) ◽  
pp. eaba6586 ◽  
Author(s):  
Yang Yang ◽  
Yumin Qian ◽  
Haijing Li ◽  
Zhenhua Zhang ◽  
Yuewen Mu ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Self Assembly ◽  
Rational Design ◽  
Single Atom ◽  
Electron Delocalization ◽  
Intrinsic Activity ◽  
Metal Atoms ◽  
Doped Graphene ◽  
Dual Atom ◽  
In Virtue Of

Single-atom catalysts (SACs) maximize the utility efficiency of metal atoms and offer great potential for hydrogen evolution reaction (HER). Bimetal atom catalysts are an appealing strategy in virtue of the synergistic interaction of neighboring metal atoms, which can further improve the intrinsic HER activity beyond SACs. However, the rational design of these systems remains conceptually challenging and requires in-depth research both experimentally and theoretically. Here, we develop a dual-atom catalyst (DAC) consisting of O-coordinated W-Mo heterodimer embedded in N-doped graphene (W1Mo1-NG), which is synthesized by controllable self-assembly and nitridation processes. In W1Mo1-NG, the O-bridged W-Mo atoms are anchored in NG vacancies through oxygen atoms with W─O─Mo─O─C configuration, resulting in stable and finely distribution. The W1Mo1-NG DAC enables Pt-like activity and ultrahigh stability for HER in pH-universal electrolyte. The electron delocalization of W─O─Mo─O─C configuration provides optimal adsorption strength of H and boosts the HER kinetics, thereby notably promoting the intrinsic activity.

scholarly journals Composite electrode based on single-atom Ni doped graphene for planar carbon-based perovskite solar cells

2021 ◽  
pp. 109972
Author(s):  
Min Guo ◽  
Chenyang Wei ◽  
Congcong Liu ◽  
Kun Zhang ◽  
Haijun Su ◽  
...  
Keyword(s):  
Solar Cells ◽  
Composite Electrode ◽  
Perovskite Solar Cells ◽  
Single Atom ◽  
Doped Graphene ◽  
Planar Carbon ◽  
Carbon Based

Single–atom manganese and nitrogen co-doped graphene as low-cost catalysts for the efficient CO oxidation at room temperature

2021 ◽  
Vol 536 ◽  
pp. 147809
Author(s):  
Mingming Luo ◽  
Zhao Liang ◽  
Chao Liu ◽  
Xiaopeng Qi ◽  
Mingwei Chen ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Room Temperature ◽  
Low Cost ◽  
Single Atom ◽  
Doped Graphene ◽  
Co Doped
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