scholarly journals Capping experiments reveal multiple surface active sites in CeO2 and their cooperative catalysis

RSC Advances ◽  
2019 ◽  
Vol 9 (27) ◽  
pp. 15229-15237 ◽  
Author(s):  
Xiaoning Ren ◽  
Zhixin Zhang ◽  
Yehong Wang ◽  
Jianmin Lu ◽  
Jinghua An ◽  
...  
Keyword(s):  
Benzoic Acid ◽  
Active Sites ◽  
Catalytic Reactions ◽  
Cooperative Catalysis ◽  
Surface Active

Capping with pyridine, benzoic acid, and DMSO in catalytic reactions reveals the locations of surface active sites of CeO2.

Subsurface Oxygen Defects Electronically Interacting with Active Sites on In2O3 for Enhanced Photothermocatalytic CO2 Reduction

2021 ◽  
Author(s):  
Weiqin Wei ◽  
Zhen Wei ◽  
Ruizhe Li ◽  
zhenhua Li ◽  
Run Shi ◽  
...  
Keyword(s):  
Active Sites ◽  
Catalyst Surface ◽  
Co2 Reduction ◽  
Catalytic Reactions ◽  
Electronic Coupling ◽  
Turnover Frequency ◽  
Structural Units ◽  
Oxygen Defects ◽  
Subsurface Oxygen ◽  
Surface Active

Abstract Oxygen defects play an important role in many catalytic reactions. Increasing surface oxygen defects can be done through reduction treatment. However, excessive reduction blocks electron channels and deactivates the catalyst surface due to electron-trapped effects by subsurface oxygen defects. How to effectively extract electrons from subsurface oxygen defects which cannot directly interact with reactants is challenging and remains elusive. Herein, we report a metallic In-embedded In2O3 nanoflake catalyst over which the turnover frequency of CO2 reduction into CO increases by a factor of 866 (7615 h-1) and 376 (2990 h-1) at same light intensity and reaction temperature, respectively, compared to In2O3. Under electron-delocalization effect of O-In-(O)Vo-In-In structural units at the interface, the electrons in the subsurface oxygen defects are extracted and gather at surface active sites. This improves the electronic coupling with CO2 and stabilizes COOH intermediate. The study opens up new insights for exquisite electronic manipulation of oxygen defects.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Cathodic Corrosion Activated Fe-based Nanoglass as Highly-Active and -Stable Oxygen Evolution Catalyst for Water Splitting

2021 ◽  
Author(s):  
Kaiyao Wu ◽  
Fei Chu ◽  
Yuying Meng ◽  
Kaveh Edalati ◽  
Qingsheng Gao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Amorphous Alloys ◽  
Precious Metal ◽  
Active Sites ◽  
Metal Free ◽  
Highly Active ◽  
Stable Oxygen ◽  
Surface Active

Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...

scholarly journals Prepare a catalyst consist of rare earth minerals to denitrate via NH3-SCR

2020 ◽  
Vol 9 (1) ◽  
pp. 191-202
Author(s):  
Jian Wang ◽  
Chao Zhu ◽  
Baowei Li ◽  
Zhijun Gong ◽  
Zhaolei Meng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Active Sites ◽  
Nh3 Scr ◽  
Composite Oxides ◽  
Rare Earth Minerals ◽  
Denitrification Activity ◽  
Denitrification Reactor ◽  
Surface Active ◽  
Rare Earth Tailings ◽  
Treatment Step

AbstractTo research the roles of rare earth minerals in denitrification via the NH3-SCR, a mixture was made by certain ratio of rare earth concentrates and rare earth tailings, then treated by microwave roasting, and acids and bases to form a denitrification catalyst. The mineral phase structure and surface morphology of the catalyst were characterized by XRD, BET, SEM and EDS. The surface properties of the catalyst were tested by TPD and XPS methods, and the denitrification activity of the catalyst was evaluated in a denitrification reactor. The results showed that the denitrification efficiency increased up to 82% with complete processing. XRD, BET, SEM, and EDS spectrum analysis stated that the treated minerals contained cerium oxides and Fe−Ce composite oxides. The surface of the modified minerals became rough and porous, the surface area increased, and the surface-active sites were exposed. The results of NH3-TPD and NO-TPD showed that the catalyst surface could gradually adsorb more NH3 and NO after each step. XPS analysis indicated that there were more Ce3+, Fe2+, and lattice oxygen in rare earth minerals catalyst after each treatment step.

Enhanced photocatalytic H2 evolution over micro-SiC by coupling with CdS under visible light irradiation

2014 ◽  
Vol 2 (18) ◽  
pp. 6296-6300 ◽  
Author(s):  
Yuan Peng ◽  
Zhongnan Guo ◽  
Jingjing Yang ◽  
Da Wang ◽  
Wenxia Yuan
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Active Sites ◽  
Fine Tuning ◽  
Surface Activation ◽  
H2 Evolution ◽  
Effective Surface ◽  
Suitable Amount ◽  
Surface Active ◽  
Photocatalytic H2 Evolution

Fine-tuning surface activation of the micro-SiC catalyst via hybridizing a suitable amount of CdS to obtain effective surface active sites.

Electrochemically controlled in-situ conversion of CO2 to defective carbon nanotubes for enhanced H2O2 production

Nanoscale ◽  
2021 ◽  
Author(s):  
Ao Yu ◽  
Guoming Ma ◽  
Longtao Zhu ◽  
Yajing Hu ◽  
Ruiling Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Active Sites ◽  
Catalytic Reactions ◽  
H2o2 Production

Defects on carbon nanotubes (CNTs) can be used as active sites to promote the occurrence of catalytic reactions and improve the ability of catalysts. Although some progress has been made...

3D self-assembled VS4 microspheres with high pseudocapacitance as highly efficient anodes for Na-ion batteries

Nanoscale ◽  
2018 ◽  
Vol 10 (46) ◽  
pp. 21671-21680 ◽  
Author(s):  
Wenbin Li ◽  
Jianfeng Huang ◽  
Liangliang Feng ◽  
Liyun Cao ◽  
Shuwei He
Keyword(s):  
Active Sites ◽  
High Capacity ◽  
Rate Capability ◽  
High Rate ◽  
High Rate Capability ◽  
Highly Efficient ◽  
Pseudocapacitive Behavior ◽  
Surface Active ◽  
Self Assembled ◽  
Cycling Life

The decreasing crystallinity of VS4 microspheres greatly increases the surface active sites, and then promotes the pseudocapacitive behavior, and finally leads to the high capacity, long cycling life and high rate capability.

Sign in / Sign up

Export Citation Format

Share Document