scholarly journals Step-by-Step Mechanism Insights into the TiO2/Ce2S3 S-Scheme Photocatalyst for Enhanced Aniline Production with Water as a Proton Source

ACS Catalysis ◽  
2021 ◽  
pp. 164-172
Author(s):  
Feiyan Xu ◽  
Kai Meng ◽  
Shuang Cao ◽  
Chenhui Jiang ◽  
Tao Chen ◽  
...  
Keyword(s):  
Proton Source ◽  
Step Mechanism

scholarly journals Step-by-step mechanism insights into TiO2/Ce2S3 S-scheme photocatalyst for enhanced aniline production with water as proton source

2021 ◽  
Author(s):  
Feiyan Xu ◽  
Kai Meng ◽  
Shuang Cao ◽  
Chen-Hui Jiang ◽  
Tao Chen ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Transient Absorption ◽  
Computational Prediction ◽  
Transient Absorption Spectroscopy ◽  
Internal Electric Field ◽  
Nitrobenzene Hydrogenation ◽  
Proton Source ◽  
Step Mechanism

Abstract Exploring new heterostructured photocatalysts for photocatalytic hydrogenation reaction with water as proton source and investigating the corresponding intrinsic step-by-step mechanism are of great interests. Here we develop a novel S-scheme heterojunction through theoretical design and implemented by solvothermal growth of Ce2S3 nanoparticles onto electrospun TiO2 nanofibers. The low-dimensional (0D/1D) heterostructure unveils enhanced photocatalytic activity for aniline production by nitrobenzene hydrogenation with water as proton source. Density functional theory (DFT) calculations indicate the electrons transfer from Ce2S3 to TiO2 upon hybridization due to their Fermi level difference and creates an internal electric field at the interface, driving the efficient separation of the photoexcited charge carriers, which is authenticated by in-situ X-ray photoelectron spectroscopy along with femtosecond transient absorption spectroscopy. The step-by-step reaction mechanism of the photocatalytic nitrobenzene hydrogenation to yield aniline is revealed by in-situ diffuse reflectance infrared Fourier transform spectroscopy, associated with DFT computational prediction.

The effect of decationation of hydroxylated HNaY zeolites on their interaction with ethylene and propylene. hydrogen complexes, oligomeration and isotope exchange

1980 ◽  
Vol 45 (11) ◽  
pp. 3101-3115 ◽  
Author(s):  
Ludmila Kubelková ◽  
Jana Nováková ◽  
Zdeněk Dolejšek ◽  
Pavel Jírů
Keyword(s):  
Isotope Exchange ◽  
Decisive Role ◽  
Single Step ◽  
Hydroxyl Groups ◽  
Isotope Exchange Reaction ◽  
Factors Affecting ◽  
Step Mechanism ◽  
Formed Hydrogen ◽  
Lower Basicity ◽  
Multiple Step

The effect of decationation on the interaction of propylene and ethylene with the hydroxylated forms of HNaY zeolites has been studied. The compounds formed in the zeolite cavities were studied using their infrared spectra, the composition of the gaseous phase was followed by mass spectrometry. The results showed that among factors affecting the interaction with propylene properties of hydroxyl groups play the decisive role. With the increasing decationation of the zeolite the strength of the OH bond in the hydrogen complex of the large-cavity hydroxyls with propylene decreased and the rate of propylene oligomeration at 310 K as well as the isotope exchange rate of propylene-d6 with the zeolite hydroxyls at 570 K increased. The propylene isotope exchange reaction proceeded by the multiple-step mechanism. In the case of ethylene only the physical sorption with a non-specific character was observed at 310 K. The adsorbed amount increased with the increasing content of Na+ ions in the zeolite (with the decreasing decationation). A part of the adsorbed molecules formed hydrogen complexes with hydroxyls of large cavities. The observed lower weakening of the OH bond was in agreement with the lower basicity of ethylene if compared with propylene. The isotope exchange of ethylene-d4 with the zeolite hydroxyls proceeded by a single-step mechanism, it had an autocatalytic character and its rate was 70 times lower than that of the isotope exchange of propylene-d6 with OH.

A Ten Step Mechanism for the Pitting Corrosion of Aluminium Alloys

1997 ◽  
Vol 15 (3-4) ◽  
pp. 471-496 ◽  
Author(s):  
M.C. Reboul, ◽  
T.J. Warner, ◽  
H. Mayer, ◽  
B. Barouk,
Keyword(s):  
Pitting Corrosion ◽  
Aluminium Alloys ◽  
Step Mechanism

scholarly journals Analysis of the possibility and molecular mechanism of carbon dioxide consumption in the Diels-Alder processes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Karolina Kula ◽  
Agnieszka Kącka-Zych ◽  
Agnieszka Łapczuk-Krygier ◽  
Radomir Jasiński
Keyword(s):  
Carbon Dioxide ◽  
Molecular Mechanism ◽  
Lewis Acids ◽  
Chemical Reactivity ◽  
Carbon Dioxide Concentration ◽  
Diels Alder ◽  
Wide Range ◽  
Bet Analysis ◽  
Earth’S Climate ◽  
Step Mechanism

Abstract The large and significant increase in carbon dioxide concentration in the Earth’s atmosphere is a serious problem for humanity. The amount of CO2 is increasing steadily which causes a harmful greenhouse effect that damages the Earth’s climate. Therefore, one of the current trends in modern chemistry and chemical technology are issues related to its utilization. This work includes the analysis of the possibility of chemical consumption of CO2 in Diels-Alder processes under non-catalytic and catalytic conditions after prior activation of the C=O bond. In addition to the obvious benefits associated with CO2 utilization, such processes open up the possibility of universal synthesis of a wide range of internal carboxylates. These studies have been performed in the framework of Molecular Electron Density Theory as a modern view of the chemical reactivity. It has been found, that explored DA reactions catalyzed by Lewis acids with the boron core, proceeds via unique stepwise mechanism with the zwitterionic intermediate. Bonding Evolution Theory (BET) analysis of the molecular mechanism associated with the DA reaction between cyclopentadiene and carbon dioxide indicates that it takes place thorough a two-stage one-step mechanism, which is initialized by formation of C–C single bond. In turn, the DA reaction between cyclopentadiene and carbon dioxide catalysed by BH3 extends in the environment of DCM, indicates that it takes place through a two-step mechanism. First path of catalysed DA reaction is characterized by 10 different phases, while the second by eight topologically different phases.

scholarly journals A quasi-monoenergetic short time duration compact proton source for probing high energy density states of matter

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. I. Apiñaniz ◽  
S. Malko ◽  
R. Fedosejevs ◽  
W. Cayzac ◽  
X. Vaisseau ◽  
...  
Keyword(s):  
Energy Density ◽  
Proton Beam ◽  
Dense Matter ◽  
High Energy ◽  
High Repetition Rate ◽  
High Energy Density ◽  
Time Duration ◽  
Ultrashort Pulse Laser ◽  
Proton Source ◽  
Short Time

AbstractWe report on the development of a highly directional, narrow energy band, short time duration proton beam operating at high repetition rate. The protons are generated with an ultrashort-pulse laser interacting with a solid target and converted to a pencil-like narrow-band beam using a compact magnet-based energy selector. We experimentally demonstrate the production of a proton beam with an energy of 500 keV and energy spread well below 10$$\% $$ % , and a pulse duration of 260 ps. The energy loss of this beam is measured in a 2 $$\upmu $$ μ m thick solid Mylar target and found to be in good agreement with the theoretical predictions. The short time duration of the proton pulse makes it particularly well suited for applications involving the probing of highly transient plasma states produced in laser-matter interaction experiments. This proton source is particularly relevant for measurements of the proton stopping power in high energy density plasmas and warm dense matter.

Fast Proton Conductors from Inorganic-Organic Composites: I. Amorphous Phosphate-Nafion and Silicophosphate-PMA/PWA Hybrids

1999 ◽  
Vol 600 ◽  
Author(s):  
Yong-Il Park ◽  
Jae-Dong Kim ◽  
Masayuki Nagai
Keyword(s):  
Phosphoric Acid ◽  
Proton Conductivity ◽  
Proton Conductors ◽  
Phosphorus Concentration ◽  
High Proton ◽  
Proton Source ◽  
Drastic Increase ◽  
Amorphous Phosphate ◽  
Exchange Resins ◽  
Very High

AbstractA drastic increase of electrical conductivity was observed in the composite of amorphous phosphate and ion-exchange resins (Nafion) as phosphorus concentration increased. Incorporation of amorphous phosphate into Nafion caused a large increase of conductivity to about 4×10−1S/cm at 23°C. However, the fabricated composite showed very low chemical stability.A high proton conductivity was also observed in a new inorganic-organic hybrids through incorporating PMA(molibdo-phosphoric acid)/PWA(tungsto-phosphoric acid) as a proton source in amorphous silicophosphate gel structure. Obtained gels were homogeneous and chemically stable. Resulting proton conductivity is very high (up to 5.5×10−3S/cm) compared to those of silicophosphate gels.

scholarly journals Thermal activation of the purified rat hepatic glucocorticoid receptor. Evidence for a two-step mechanism.

1985 ◽  
Vol 260 (30) ◽  
pp. 16255-16262 ◽  
Author(s):  
T J Schmidt ◽  
A Miller-Diener ◽  
M L Webb ◽  
G Litwack
Keyword(s):  
Glucocorticoid Receptor ◽  
Thermal Activation ◽  
Step Mechanism

scholarly journals Structural Insight into the Two-Step Mechanism of PAI-1 Inhibition by Small Molecule TM5484

2021 ◽  
Vol 22 (3) ◽  
pp. 1482 ◽  
Author(s):  
Machteld Sillen ◽  
Toshio Miyata ◽  
Douglas E. Vaughan ◽  
Sergei V. Strelkov ◽  
Paul J. Declerck
Keyword(s):  
Binding Site ◽  
Small Molecule ◽  
Intracellular Signaling ◽  
Plasminogen Activator Inhibitor ◽  
Plasminogen Activator Inhibitor 1 ◽  
Joint Region ◽  
Flexible Joint ◽  
Step Mechanism ◽  
Pai 1

Plasminogen activator inhibitor-1 (PAI-1), a key regulator of the fibrinolytic system, is the main physiological inhibitor of plasminogen activators. By interacting with matrix components, including vitronectin (Vn), PAI-1 plays a regulatory role in tissue remodeling, cell migration, and intracellular signaling. Emerging evidence points to a role for PAI-1 in various pathological conditions, including cardiovascular diseases, cancer, and fibrosis. Targeting PAI-1 is therefore a promising therapeutic strategy in PAI-1-related pathologies. A class of small molecule inhibitors including TM5441 and TM5484, designed to bind the cleft in the central β-sheet A of PAI-1, showed to be potent PAI-1 inhibitors in vivo. However, their binding site has not yet been confirmed. Here, we report two X-ray crystallographic structures of PAI-1 in complex with TM5484. The structures revealed a binding site at the flexible joint region, which is distinct from the presumed binding site. Based on the structural analysis and biochemical data we propose a mechanism for the observed dose-dependent two-step mechanism of PAI-1 inhibition. By binding to the flexible joint region in PAI-1, TM5484 might restrict the structural flexibility of this region, thereby inducing a substrate form of PAI-1 followed by a conversion to an inert form.

scholarly journals Mechanistic studies of a “Declick” reaction

2019 ◽  
Vol 10 (38) ◽  
pp. 8817-8824 ◽  
Author(s):  
Margaret K. Meadows ◽  
Xiaolong Sun ◽  
Igor V. Kolesnichenko ◽  
Caroline M. Hinson ◽  
Kenneth A. Johnson ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Mechanistic Studies ◽  
Step Mechanism

Detailed kinetic analysis reveals a complex multi-step mechanism for an amine-thiol “declick” reaction.

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