scholarly journals NaBr Poisoning of Au/TiO2 Catalysts: Effects on Kinetics, Poisoning Mechanism, and Estimation of the Number of Catalytic Active Sites

ACS Catalysis ◽  
2012 ◽  
Vol 2 (4) ◽  
pp. 684-694 ◽  
Author(s):  
Bert D. Chandler ◽  
Shane Kendell ◽  
Hieu Doan ◽  
Rachel Korkosz ◽  
Lars C. Grabow ◽  
...  
Keyword(s):  
Active Sites ◽  
Catalytic Active Sites

scholarly journals Facile Synthesis of Uniform Mesoporous Nb2O5 Micro-Flowers for Enhancing Photodegradation of Methyl Orange

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3783
Author(s):  
Jian-Qing Qiu ◽  
Huan-Qing Xie ◽  
Ya-Hao Wang ◽  
Lan Yu ◽  
Fang-Yuan Wang ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Active Sites ◽  
High Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Flower Structure ◽  
Electron Microscopies ◽  
Bet Method ◽  
One Step ◽  
Catalytic Active Sites

The removal of organic pollutants using green environmental photocatalytic degradation techniques urgently need high-performance catalysts. In this work, a facile one-step hydrothermal technique has been successfully applied to synthesize a Nb2O5 photocatalyst with uniform micro-flower structure for the degradation of methyl orange (MO) under UV irradiation. These nanocatalysts are characterized by transmission and scanning electron microscopies (TEM and SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) method, and UV-Vis diffuse reflectance spectroscopy (DRS). It is found that the prepared Nb2O5 micro-flowers presents a good crystal phases and consist of 3D hierarchical nanosheets with 400–500 nm in diameter. The surface area is as large as 48.6 m2 g−1. Importantly, the Nb2O5 micro-flowers exhibit superior catalytic activity up to 99.9% for the photodegradation of MO within 20 mins, which is about 60-fold and 4-fold larger than that of without catalysts (W/O) and commercial TiO2 (P25) sample, respectively. This excellent performance may be attributed to 3D porous structure with abundant catalytic active sites.

ChemInform Abstract: UV Raman Spectroscopic Characterization of Catalysts and Catalytic Active Sites

ChemInform ◽  
2015 ◽  
Vol 46 (8) ◽  
pp. no-no
Author(s):  
Shaoqing Jin ◽  
Zhaochi Feng ◽  
Fengtao Fan ◽  
Can Li
Keyword(s):  
Active Sites ◽  
Spectroscopic Characterization ◽  
Raman Spectroscopic ◽  
Catalytic Active Sites ◽  
Uv Raman

scholarly journals A Combined Computational and Experimental Study of Methane Activation during Oxidative Coupling of Methane (OCM) by Surface Metal Oxide Catalysts

2021 ◽  
Author(s):  
Daniyal Kiani ◽  
Sagar Sourav ◽  
Jonas Baltrusaitis ◽  
Israel E Wachs
Keyword(s):  
Experimental Study ◽  
Metal Oxide ◽  
Oxidative Coupling ◽  
Active Sites ◽  
Computational Models ◽  
Oxidative Coupling Of Methane ◽  
Catalytic Active Sites ◽  
Surface Metal ◽  
Heterolytic Dissociation ◽  
First Time

The experimentally validated computational models developed herein, for the first time, show that Mn-promotion does not enhance the activity of the surface Na2WO4 catalytic active sites for CH4 heterolytic dissociation...

scholarly journals Vertical Bi2Se3 flake array as a Pt-free counter electrode for dye-sensitized solar cells

RSC Advances ◽  
2017 ◽  
Vol 7 (82) ◽  
pp. 51958-51964 ◽  
Author(s):  
Manshu Han ◽  
Shuang Lu ◽  
Jiangang Ma ◽  
Haiyang Xu ◽  
Yinglin Wang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solar Cells ◽  
Active Sites ◽  
Counter Electrode ◽  
Dye Sensitized Solar Cells ◽  
High Electrical Conductivity ◽  
Dye Sensitized ◽  
Catalytic Active Sites ◽  
Sensitized Solar Cells

Vertical Bi2Se3 flake arrays work as counter-electrode in DSSCs due to its high electrical conductivity and abundance of catalytic active sites.

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.

scholarly journals Cr-Free, Cu Promoted Fe Oxide-Based Catalysts for High-Temperature Water-Gas Shift (HT-WGS) Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 305
Author(s):  
Sagar Sourav ◽  
Israel E. Wachs
Keyword(s):  
Active Sites ◽  
Catalyst Surface ◽  
Analysis Data ◽  
Fe Oxide ◽  
Redox Sites ◽  
Wgs Reaction ◽  
Catalytic Active Sites ◽  
Redox Ability ◽  
Water Gas ◽  
Temperature Water

Ca, Ni, Co, and Ge promoters were examined as potential candidates to substitute for the current toxic Cr in Cu-promoted Fe oxide-based catalysts for the HT-WGS reaction. The Ca and Ni promoters were found to improve catalyst performance relative to promotion with Cr. The HS-LEIS surface analysis data demonstrate that Ca and Ge tend to segregate on the surface, while Ni, Co, and Cr form solid solutions in the Fe3O4 bulk lattice. The corresponding number of catalytic active sites, redox, and WGS activity values of the catalysts were determined with CO-TPR, CO+H2O-TPSR, and SS-WGS studies, respectively. The poorer HT-WGS performances of the Ge and Co promoters are related to the presence of surface Ge and Co that inhibits catalyst redox ability, with the Co also not stabilizing the surface area of the Fe3O4 support. The Ni promoter uniformly disperses the Cu nanoparticles on the catalyst surface and increases the number of FeOx-Cu interfacial redox sites. The Ca promoter on the catalyst surface, however, enhances the activity of the FeOx-Cu interfacial redox sites. The CO+H2O TPSR results reveal that the redox ability of the active sites follows the SS-WGS performance of the catalysts and show the following trend: 3Cu8CaFe > 3Cu8NiFe ≥ 3Cu8CrFe > 3Cu8CoFe >> 3Cu8GeFe. Furthermore, all the catalysts followed a redox-type reaction mechanism for the HT-WGS reaction.

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