scholarly journals On the evaluation of hydrogen evolution reaction performance of metal-nitrogen-doped carbon electrocatalysts using machine learning technique

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alireza Baghban ◽  
Sajjad Habibzadeh ◽  
Farzin Zokaee Ashtiani
Keyword(s):  
Adsorption Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Fuzzy Inference ◽  
Great Accuracy ◽  
Single Atom ◽  
Covalent Radius ◽  
Gray Wolf ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon

AbstractSingle-atom catalysts (SACs) introduce as a promising category of electrocatalysts, especially in the water-splitting process. Recent studies have exhibited that nitrogen-doped carbon-based SACs can act as a great HER electrocatalyst. In this regard, Adaptive Neuro-Fuzzy Inference optimized by Gray Wolf Optimization (GWO) method was used to predict hydrogen adsorption energy (ΔG) obtained from density functional theory (DFT) for single transition-metal atoms including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, and Au embedded in N-doped carbon of different sizes. Various descriptors such as the covalent radius, Zunger radius of the atomic d-orbital, the formation energy of the single-atom site, ionization energy, electronegativity, the d-band center from − 6 to 6 eV, number of valence electrons, Bader charge, number of occupied d states from 0 to − 2 eV, and number of unoccupied d states from 0 to 2 eV were chosen as input parameters based on sensitivity analysis. The R-squared and MSE of the developed model were 0.967 and 0.029, respectively, confirming its great accuracy in determining hydrogen adsorption energy of metal/NC electrocatalysts.

Engineering Mn Atomic Sites in Multi-Dimensional Nitrogen-Doped Carbon for Highly Efficient Oxygen Reduction Reaction

2022 ◽  
Author(s):  
Huixin Ma ◽  
Daijie Deng ◽  
Honghui Zhang ◽  
Feng Chen ◽  
Junchao Qian ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Single Atom ◽  
Two Dimensional ◽  
One Dimensional ◽  
Nitrogen Doped ◽  
Half Wave ◽  
Nitrogen Doped Carbon

Nitrogen-coordinated single-atom manganese in multi-dimensional nitrogen-doped carbon electrocatalysts (Mn-NC) was successful constructed by combing two-dimensional nanosheets and one-dimensional nanofibers. The Mn-NC exhibited excellent oxygen reduction reaction catalytic activity with half-wave...

Nitrogen-doped carbon supports with terminated hydrogen and their effects on active gold species: a density functional study

2014 ◽  
Vol 16 (46) ◽  
pp. 25498-25507 ◽  
Author(s):  
Junjie Gu ◽  
Qian Du ◽  
You Han ◽  
Zhenghua He ◽  
Wei Li ◽  
...  
Keyword(s):  
Valence State ◽  
Density Functional ◽  
Functional Study ◽  
Carbon Supports ◽  
Acetylene Hydrochlorination ◽  
Density Functional Study ◽  
Nitrogen Doped ◽  
Doped Graphene ◽  
The Stability ◽  
Nitrogen Doped Carbon

The stabilities of gold species on N-doped graphene increase with its valence state. Au2Cl6 interacts preferentially with HCl on N-doped supports, enhancing the stability of Au catalysts for acetylene hydrochlorination.

scholarly journals Ultra-Stable Potassium Ion Storage of Nitrogen-Doped Carbon Nanofiber Derived from Bacterial Cellulose

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1130
Author(s):  
Liang Ma ◽  
Jinliang Li ◽  
Zhibin Li ◽  
Yingying Ji ◽  
Wenjie Mai ◽  
...  
Keyword(s):  
Energy Density ◽  
Bacterial Cellulose ◽  
Density Functional ◽  
Carbon Nanofiber ◽  
Specific Capacity ◽  
Relative Energy ◽  
Large Radius ◽  
Nitrogen Doped ◽  
Ion Storage ◽  
Nitrogen Doped Carbon

As a promising energy storage system, potassium (K) ion batteries (KIBs) have received extensive attention due to the abundance of potassium resource in the Earth’s crust and the similar properties of K to Li. However, the electrode always presents poor stability for K-ion storage due to the large radius of K-ions. In our work, we develop a nitrogen-doped carbon nanofiber (N-CNF) derived from bacterial cellulose by a simple pyrolysis process, which allows ultra-stable K-ion storage. Even at a large current density of 1 A g−1, our electrode exhibits a reversible specific capacity of 81 mAh g−1 after 3000 cycles for KIBs, with a capacity retention ratio of 71%. To investigate the electrochemical enhancement performance of our N-CNF, we provide the calculation results according to density functional theory, demonstrating that nitrogen doping in carbon is in favor of the K-ion adsorption during the potassiation process. This behavior will contribute to the enhancement of electrochemical performance for KIBs. In addition, our electrode exhibits a low voltage plateau during the potassiation–depotassiation process. To further evaluate this performance, we calculate the “relative energy density” for comparison. The results illustrate that our electrode presents a high “relative energy density”, indicating that our N-CNF is a promising anode material for KIBs.

ELECTRONIC STRUCTURE OF SHORT CARBON NANOBELLS

2003 ◽  
Vol 17 (09) ◽  
pp. 375-382 ◽  
Author(s):  
G. L. ZHAO ◽  
D. BAGAYOKO ◽  
E. G. WANG
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Local Density ◽  
Emission Characteristics ◽  
Local Density Of States ◽  
Nitrogen Doped ◽  
Local Density Functional ◽  
Nitrogen Doped Carbon ◽  
Short Carbon ◽  
Open Edge

We performed local density functional calculations for the electronic structure of short carbon nanobells. The calculated local density of states of the nanobells revealed field emission characteristics that agree with experimental observations. We also performed total energy calculations to study the structural stability and a related possible growth mechanism of the nanobells. In the nitrogen-doped carbon nanobells, nitrogen atoms that are attracted to the open-edge sites of the carbon nanobells appear to stop the growth of the nanostructures.

scholarly journals Insights into Hydrogen Evolution Reaction on 2D Transition Metal Dichalcogenides

2021 ◽  
Author(s):  
Zhenbin Wang ◽  
Michael Tang ◽  
Ang Cao ◽  
Karen Chan ◽  
Jens Kehlet Nørskov
Keyword(s):  
Transition Metal ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Adsorption Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Activation Barrier ◽  
Transition Metal Dichalcogenides ◽  
Adsorbed Hydrogen ◽  
Metal Dichalcogenides

<p>Understanding the hydrogen evolution reaction (HER) behaviors over 2D transition metal dichalcogenides (2D-TMDs) is critical for the development of non-precious HER electrocatalysts with better activity. In this work, by combining density functional theory calculations with microkinetic modelling, we thoroughly investigated the HER mechanism on 2D-TMDs. We find there is an important dependence of simulated cell size on the calculated hydrogen adsorption energy and the activation barrier for MoS<sub>2</sub>. Distinct from previous “H migration” mechanisms proposed for the Heyrovsky reaction − the rate-determining step for MoS<sub>2</sub>, we propose the Mo site only serves as the stabilized transition state rather than H adsorption. In comparison to transition metal electrocatalysts, we find that the activation barrier of the Heyrovsky reaction on 2D-TMDs scales with the hydrogen adsorption energy exactly as for transition metals except that all activation energies are displaced upwards by <i>ca.</i> 0.4 eV. This higher Heyrovsky activation barrier is responsible for the substantially lower activity of 2D-TMDs. We further show that this higher activation barrier stems from the more positively charged adsorbed hydrogen on the chalcogenides interacting repulsively with the incoming proton. Based on these insights, we discuss potential strategies for the design of non-precious HER catalysts with activity comparable to Pt.</p>

scholarly journals Nitrogen-doped Carbon Nanospheres-Modified Graphitic Carbon Nitride with Outstanding Photocatalytic Activity

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiaoran Liu ◽  
Hao Tian ◽  
Zhenghua Dai ◽  
Hongqi Sun ◽  
Jian Liu ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Density Functional ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Carbon Nanospheres ◽  
Electron Hole ◽  
Practical Applications ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon

AbstractMetals and metal oxides are widely used as photo/electro-catalysts for environmental remediation. However, there are many issues related to these metal-based catalysts for practical applications, such as high cost and detrimental environmental impact due to metal leaching. Carbon-based catalysts have the potential to overcome these limitations. In this study, monodisperse nitrogen-doped carbon nanospheres (NCs) were synthesized and loaded onto graphitic carbon nitride (g-C3N4, GCN) via a facile hydrothermal method for photocatalytic removal of sulfachloropyridazine (SCP). The prepared metal-free GCN-NC exhibited remarkably enhanced efficiency in SCP degradation. The nitrogen content in NC critically influences the physicochemical properties and performances of the resultant hybrids. The optimum nitrogen doping concentration was identified at 6.0 wt%. The SCP removal rates can be improved by a factor of 4.7 and 3.2, under UV and visible lights, by the GCN-NC composite due to the enhanced charge mobility and visible light harvesting. The mechanism of the improved photocatalytic performance and band structure alternation were further investigated by density functional theory (DFT) calculations. The DFT results confirm the high capability of the GCN-NC hybrids to activate the electron–hole pairs by reducing the band gap energy and efficiently separating electron/hole pairs. Superoxide and hydroxyl radicals are subsequently produced, leading to the efficient SCP removal.

scholarly journals Single-atom catalysts templated by metal–organic frameworks for electrochemical nitrogen reduction

2019 ◽  
Vol 7 (46) ◽  
pp. 26371-26377 ◽  
Author(s):  
Rui Zhang ◽  
Long Jiao ◽  
Weijie Yang ◽  
Gang Wan ◽  
Hai-Long Jiang
Keyword(s):  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Single Atom ◽  
Excellent Performance ◽  
Acidic Media ◽  
Nitrogen Reduction ◽  
Nitrogen Doped ◽  
Metal Organic ◽  
Nitrogen Doped Carbon ◽  
Organic Framework

Metal–organic framework precursors were employed to fabricate single-atom catalysts, where Fe implanted nitrogen-doped carbon (Fe1-N-C) exhibits excellent performance for electrocatalytic nitrogen reduction in acidic media.

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