scholarly journals Manganese vacancy-confined single-atom Ag in cryptomelane nanorods for efficient Wacker oxidation of styrene derivatives

2021 ◽  
Author(s):  
Hongling Yang ◽  
Xun Zhang ◽  
Yi Yu ◽  
Zheng Chen ◽  
Qinggang Liu ◽  
...  
Keyword(s):  
Molecular Sieve ◽  
Active Sites ◽  
Single Atom ◽  
Wacker Oxidation ◽  
Catalytically Active ◽  
Styrene Derivatives

Single-atom catalysts provide a pathway to elucidate the nature of catalytically active sites. However, keeping them stabilized during operation proves to be challenging. Herein, we employ cryptomelane-type octahedral molecular sieve...

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 Shifting the scaling relations of single-atom catalysts for facile methane activation by tuning the coordination number

2021 ◽  
Author(s):  
Changhyeok Choi ◽  
Sungho Yoon ◽  
Yousung Jung
Keyword(s):  
Transition State ◽  
Coordination Number ◽  
Active Sites ◽  
Methane Activation ◽  
Single Atom ◽  
Scaling Relations ◽  
Scaling Relationship ◽  
Relationship Of

The scaling relationship of methane activation via a radical-like transition state shifts toward a more reactive region with decreasing coordination number of the active sites.

First-principles screening of single transition metal atoms anchored on two-dimensional C9N4 for the nitrogen reduction reaction

2021 ◽  
Vol 23 (14) ◽  
pp. 8784-8791
Author(s):  
Qingling Meng ◽  
Ling Zhang ◽  
Jinge Wu ◽  
Shuwei Zhai ◽  
Xiamin Hao ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Transition Metal ◽  
First Principles ◽  
Reduction Reaction ◽  
Single Atom ◽  
Two Dimensional ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Catalytically Active ◽  
Single Transition

Theoretical screening of transition metal atoms anchored on monolayer C9N4 as highly stable, catalytically active and selective single-atom catalysts for nitrogen fixation.

scholarly journals Engineering single-atomic ruthenium catalytic sites on defective nickel-iron layered double hydroxide for overall water splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Panlong Zhai ◽  
Mingyue Xia ◽  
Yunzhen Wu ◽  
Guanghui Zhang ◽  
Junfeng Gao ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Layered Double Hydroxide ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
Rational Design ◽  
Single Atom ◽  
Nickel Iron ◽  
Double Hydroxide

AbstractRational design of single atom catalyst is critical for efficient sustainable energy conversion. However, the atomic-level control of active sites is essential for electrocatalytic materials in alkaline electrolyte. Moreover, well-defined surface structures lead to in-depth understanding of catalytic mechanisms. Herein, we report a single-atomic-site ruthenium stabilized on defective nickel-iron layered double hydroxide nanosheets (Ru1/D-NiFe LDH). Under precise regulation of local coordination environments of catalytically active sites and the existence of the defects, Ru1/D-NiFe LDH delivers an ultralow overpotential of 18 mV at 10 mA cm−2 for hydrogen evolution reaction, surpassing the commercial Pt/C catalyst. Density functional theory calculations reveal that Ru1/D-NiFe LDH optimizes the adsorption energies of intermediates for hydrogen evolution reaction and promotes the O–O coupling at a Ru–O active site for oxygen evolution reaction. The Ru1/D-NiFe LDH as an ideal model reveals superior water splitting performance with potential for the development of promising water-alkali electrocatalysts.

Tuning electronic states of catalytic sites enhances SCR activity of hexagonal WO3by Mo framework substitution

2017 ◽  
Vol 7 (12) ◽  
pp. 2467-2473 ◽  
Author(s):  
Yaxin Chen ◽  
Zichenxi Dong ◽  
Zhiwei Huang ◽  
Meijuan Zhou ◽  
Jiayi Gao ◽  
...  
Keyword(s):  
Active Sites ◽  
Electronic States ◽  
Catalytic Sites ◽  
Catalytically Active

The electronic states of the catalytically active sites of HWO were tuned by Mo framework substitution.

ChemInform Abstract: Catalytically Active Sites and Their Complexity: A Micro-review.

ChemInform ◽  
2014 ◽  
Vol 45 (11) ◽  
pp. no-no ◽  
Author(s):  
Marco Piumetti ◽  
Francesca Stefania Freyria ◽  
Barbara Bonelli
Keyword(s):  
Active Sites ◽  
Catalytically Active

Atomic regulation of metal-organic framework derived carbon-based single-atom catalysts for electrochemical CO2 reduction reaction

2021 ◽  
Author(s):  
Danni Zhou ◽  
Xinyuan Li ◽  
Huishan Shang ◽  
Fengjuan Qin ◽  
Wenxing Chen
Keyword(s):  
Active Sites ◽  
Metal Organic Framework ◽  
Co2 Reduction ◽  
Carbon Dioxide Reduction ◽  
Reduction Reaction ◽  
Single Atom ◽  
Electrochemical Co2 Reduction ◽  
Metal Organic ◽  
Co2 Reduction Reaction ◽  
Organic Framework

Metal-organic framework (MOF) derived single-atom catalysts (SACs), featured unique active sites and adjustable topological structures, exhibit high electrocatalytic performance on carbon dioxide reduction reactions (CO2RR). By modulating elements and atomic...

The structure and activity of potassium supported on SBA-15 molecular sieve: Density functional theory study

2014 ◽  
Vol 13 (01) ◽  
pp. 1350076 ◽  
Author(s):  
Bing Liu ◽  
Daxi Wang ◽  
Zhongxue Wang ◽  
Zhen Zhao ◽  
Yu Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lewis Acid ◽  
Molecular Sieve ◽  
Active Sites ◽  
Density Functional ◽  
Structural Model ◽  
Vibrational Frequencies ◽  
Oxygen Molecule ◽  
Lewis Base ◽  
Functional Theory

The geometries, vibrational frequencies, electronic properties and reactivity of potassium supported on SBA-15 have been theoretically investigated by the density functional theory (DFT) method. The structural model of the potassium supported on SBA-15 was constructed based on our previous work [Wang ZX, Wang DX, Zhao Z, Chen Y, Lan J, A DFT study of the structural units in SBA-15 mesoporous molecular sieve, Comput. Theor. Chem.963, 403, 2011]. This paper is the extension of our previous work. The most favored location of potassium atom was obtained by the calculation of substitution energy. The calculated vibrational frequencies of K /SBA-15 are in good agreement with the experimental results. By analyzing the properties of electronic structure, we found that the O atom of Si - O (2)- K group acts as the Lewis base center and the K atom acts as the Lewis acid center. The reactivity of K /SBA-15 was investigated by calculating the activation of oxygen molecule. The oxygen molecule can be activated by K /SBA-15 with an energy barrier of 103.2 kJ/mol. In the final state, the activated oxygen atoms become new Lewis acid centers, which are predicted to act as the active sites in the catalytic reactions. This study provides a deep insight into the properties of supported potassium catalysts and offers fundamental information for further research.

Optimization of Catalytically Active Sites Positioning in Porous Cathodes of Lithium/Air Batteries Filled with Different Electrolytes

2015 ◽  
Vol 162 (14) ◽  
pp. A2796-A2804 ◽  
Author(s):  
Tatjana Dabrowski ◽  
Alexander Struck ◽  
Daniela Fenske ◽  
Peter Maaß ◽  
Lucio Colombi Ciacchi
Keyword(s):  
Active Sites ◽  
Catalytically Active ◽  
Porous Cathodes ◽  
Lithium Air Batteries
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