Elucidating the active sites for CO2 electroreduction on ligand-protected Au25 nanoclusters

2018 ◽  
Vol 8 (15) ◽  
pp. 3795-3805 ◽  
Author(s):  
Natalie Austin ◽  
Shuo Zhao ◽  
James R. McKone ◽  
Rongchao Jin ◽  
Giannis Mpourmpakis
Keyword(s):  
Electrochemical Reduction ◽  
Active Sites ◽  
Au Nanoclusters ◽  
Co2 Electroreduction ◽  
Catalytic Sites

This work reveals the mechanism of CO2 electrochemical reduction on ligand-protected Au nanoclusters and catalytic sites responsible for increased selectivity towards CO.

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.

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.

scholarly journals Large-area printing of ferroelectric surface and super-domains for efficient solar water splitting

2020 ◽  
Author(s):  
Yu Tian ◽  
Yaqing Wei ◽  
Minghui Pei ◽  
Rongrong Cao ◽  
Zhenao Gu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Electric Fields ◽  
Electronic Structures ◽  
Active Sites ◽  
Large Area ◽  
Solar Water Splitting ◽  
High Efficient ◽  
Catalytic Sites ◽  
Order Of Magnitude ◽  
Magnitude Increase

Abstract Surface electronic structures of the photoelectrodes determine the activity and efficiency of the photoelectrochemical water splitting, but the controls of their surface structures and interfacial chemical reactions remain challenging. Here, we use ferroelectric BiFeO3 as a model system to demonstrate an efficient and controllable water splitting reaction by large-area constructing the hydroxyls-bonded surface. The up-shift of band edge positions at this surface enables and enhances the interfacial holes and electrons transfer through the hydroxyl-active-sites, leading to simultaneously enhanced oxygen and hydrogen evolutions. Furthermore, printing of ferroelectric super-domains with microscale checkboard up/down electric fields separates the distribution of reduction/oxidation catalytic sites, enhancing the charge separation and giving rise to an order of magnitude increase of the photocurrent. This large-area printable ferroelectric surface and super-domains offer an alternative platform for controllable and high-efficient photocatalysis.

The protease MBTPS2 is an important regulator of several cellular processes, especially in health and sickness

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Active Sites ◽  
Peptide Bond ◽  
Cellular Processes ◽  
Disease States ◽  
Tremendous Progress ◽  
Catalytic Sites ◽  
Important Regulator ◽  
Catalytic Active Sites ◽  
Proteolytic Action ◽  
Health And Sickness

Since the identification of MBTPS2 in 1997, tremendous progress has been made in determining the protease's functions. The protease has developed from an element of the SREBP cleavage machinery to an important regulator of several cellular processes, especially in health and sickness. With this newfound information from biochemical and structural biology, S2P's proteolytic action through peptide bond hydrolysis can occur in the membrane, providing a conceptual framework for appreciating S2P's roles in other aspects, and showing that many other substrates rely on S2P for their survival. In addition, we discovered the identity of both of S2P's catalytic active sites, an essential finding as the activity of the proteolysis as well as the pathogenesis of MBTPS2-caused illnesses seems to be connected to the molecular and biochemical features of the catalytic sites. Additionally, MBTPS2 causes different diseases, possibly illustrating the pleiotropic nature of the protein. Also, while the ailments reported thus far are all due to mutations that cause MBTPS2 to lose function, other variants that cause MBTPS2 to be hyperactive have not been examined. Nevertheless, recognizing the related sickness pathomechanism is a challenge. Pursuing these challenging technical areas would most definitely enhance our understanding of MBTPS2 in disease states. MBTPS2 appears to be nearing the solution to many of the remaining fundamental questions surrounding the mechanism of its action, as well as being a therapeutic target for new therapies.

A mutually isolated nanodiamond/porous carbon nitride nanosheet hybrid with enriched active sites for promoted catalysis in styrene production

2020 ◽  
Vol 10 (4) ◽  
pp. 1048-1055 ◽  
Author(s):  
Guifang Ge ◽  
Xinwen Guo ◽  
Chunshan Song ◽  
Zhongkui Zhao
Keyword(s):  
Molten Salt ◽  
Energy Saving ◽  
Porous Carbon ◽  
Active Sites ◽  
Carbon Nitride ◽  
Catalytic Sites ◽  
Styrene Production

A mutually isolated nanodiamond/porous carbon nitride nanosheet hybrid with enriched catalytic sites is fabricated by a facile two-step molten salt-oxidation strategy, generating an excellent catalyst for clean and energy-saving styrene production.

scholarly journals Atomically dispersed nickel as coke-resistant active sites for methane dry reforming

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohcin Akri ◽  
Shu Zhao ◽  
Xiaoyu Li ◽  
Ketao Zang ◽  
Adam F. Lee ◽  
...  
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
Low Cost ◽  
Coke Formation ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Highly Active ◽  
Catalytic Sites ◽  
Earth Abundant ◽  
Poor Stability

AbstractDry reforming of methane (DRM) is an attractive route to utilize CO2 as a chemical feedstock with which to convert CH4 into valuable syngas and simultaneously mitigate both greenhouse gases. Ni-based DRM catalysts are promising due to their high activity and low cost, but suffer from poor stability due to coke formation which has hindered their commercialization. Herein, we report that atomically dispersed Ni single atoms, stabilized by interaction with Ce-doped hydroxyapatite, are highly active and coke-resistant catalytic sites for DRM. Experimental and computational studies reveal that isolated Ni atoms are intrinsically coke-resistant due to their unique ability to only activate the first C-H bond in CH4, thus avoiding methane deep decomposition into carbon. This discovery offers new opportunities to develop large-scale DRM processes using earth abundant catalysts.

New insights into lactase and glycosylceramidase activities of rat lactase-phlorizin hydrolase

1989 ◽  
Vol 257 (4) ◽  
pp. G616-G623 ◽  
Author(s):  
H. A. Buller ◽  
A. G. Van Wassenaer ◽  
S. Raghavan ◽  
R. K. Montgomery ◽  
M. A. Sybicki ◽  
...  
Keyword(s):  
Active Sites ◽  
Specific Activity ◽  
Fold Increase ◽  
Developmental Pattern ◽  
Lactose Hydrolysis ◽  
Adult Males ◽  
Lactase Activity ◽  
Developmental Patterns ◽  
Catalytic Sites ◽  
Hydrolysis Of

Lactase-phlorizin hydrolase, a small intestinal disaccharidase, has been considered mainly an enzyme important only for the hydrolysis of lactose. After weaning in most mammals lactase-specific activity falls markedly, and, functionally, adult mammals are considered to be lactase deficient. However, the persistence of low levels of lactase activity in adulthood has never been explained. In addition, it has been suggested that lactase-phlorizin hydrolase is associated with glycosylceramidase activity when the enzyme is prepared by column chromatography, but it is unclear whether this represents copurified activities or two catalytic sites on one peptide. The developmental patterns of lactase-phlorizin hydrolase and other disaccharidases were investigated in homogenates of total rat small intestine; lactase and several glycosylceramidases were measured in immunoprecipitates from these homogenates using a monoclonal antibody. The developmental pattern of total lactase activity showed a steady 2.3-fold increase to adult levels (specific activity decreased eightfold), whereas total phlorizin-hydrolase activity increased 10.7-fold (specific activity decreased threefold). As expected, levels of both total and specific sucrase and maltase activities increased during development. In lactating rats total lactase activity showed a significant increase compared with adult males. The developmental pattern of the enzyme activities for the glycolipid substrates was similar to that found for lactase, and the immunoprecipitated enzyme showed a 40- to 55-fold higher affinity for the glycolipids than for lactose. Galactosyl- and lactosylceramide inhibited lactose hydrolysis by 38%, without a competitive pattern, suggesting two different active sites for lactose and glycolipid hydrolysis, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals A Disquisition on the Active Sites of Heterogeneous Catalysts for Electrochemical Reduction of CO 2 to Value‐Added Chemicals and Fuel

2020 ◽  
Vol 10 (11) ◽  
pp. 1902106 ◽  
Author(s):  
Rahman Daiyan ◽  
Wibawa Hendra Saputera ◽  
Hassan Masood ◽  
Josh Leverett ◽  
Xunyu Lu ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Value Added

scholarly journals Highly effective sites and selectivity of nitrogen-doped graphene/CNT catalysts for CO2electrochemical reduction

2016 ◽  
Vol 7 (2) ◽  
pp. 1268-1275 ◽  
Author(s):  
Guo-Liang Chai ◽  
Zheng-Xiao Guo
Keyword(s):  
Electrochemical Reduction ◽  
Active Sites ◽  
Nitrogen Doped ◽  
Highly Effective ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

The selectivity of CO2electrochemical reduction can be tuned for N-doped graphene/CNT catalysts after active sites are determined.

A hybrid composite catalyst of Fe3O4 nanoparticles-based carbon for electrochemical reduction of oxygen

2017 ◽  
Vol 41 (12) ◽  
pp. 4959-4965 ◽  
Author(s):  
Zongkun Chen ◽  
Fei Lin ◽  
Dandan He ◽  
Heqing Jiang ◽  
Jingjing Zhang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrochemical Reduction ◽  
Fe3o4 Nanoparticles ◽  
Hybrid Composite ◽  
Active Sites ◽  
Composite Catalyst ◽  
Carbon Catalyst ◽  
Orr Activity ◽  
Electrochemical Reduction Of Oxygen

We report an Fe3O4 nanoparticles-based carbon catalyst with good electrical conductivity, abundant active sites and efficient catalytic ORR activity.

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