scholarly journals Insights into the Morphological Effect of Co3O4 Crystallite on Catalytic Oxidation of Vinyl Chloride

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 408 ◽  
Author(s):  
Chao Wang ◽  
Wenchao Hua ◽  
Guangtao Chai ◽  
Chuanhui Zhang ◽  
Yanglong Guo
Keyword(s):  
Catalytic Activity ◽  
Vinyl Chloride ◽  
Material Characterization ◽  
Active Sites ◽  
Morphological Effect ◽  
Catalytic Activities ◽  
Adsorbed Oxygen Species ◽  
One Step ◽  
Crystallographic Structures ◽  
And Performance

Co3O4 catalysts of cube and sphere shapes were prepared by one-step hydrothermal synthesis with different controlled amounts of Co(NO3)2·6H2O and NaOH. The morphological effects on both physicochemical properties and catalytic activities of vinyl chloride oxidation were investigated by material characterization and performance evaluation. The obtained results showed that the morphology, resulting in the exposure difference of crystal planes, significantly affected the catalytic property. The catalytic activity for vinyl chloride oxidation followed a descending order of Co3O4 cube (Co3O4-c) > Co3O4 sphere (Co3O4-s) > Co3O4 commercial (Co3O4-com). The cube-shaped Co3O4 presented higher catalytic activity and stability than Co3O4 spheres despite their similar crystallographic structures as well as physicochemical and redox properties. Accordingly, the different catalytic behaviors should be attributed to a morphological effect. The Co3O4 cube with a preferential exposure of (001) plane presented higher abundance of surface Co2+ cations and adsorbed oxygen species, which acted as the active sites responsible for the improvement of its catalytic activity.

Catalytic activity of CuGHK peptide-based porous material

2021 ◽  
Author(s):  
Francisco G. Cirujano ◽  
Nuria Martin ◽  
Neyvis Almora-Barrios ◽  
Carlos Martí-Gastaldo
Keyword(s):  
Catalytic Activity ◽  
Porous Material ◽  
Active Sites ◽  
Room Temperature ◽  
Side Chain ◽  
Periodic Distribution ◽  
Lysine Side Chain ◽  
One Step

Room temperature one-step synthesis of the peptide-based porous material with a periodic distribution of pockets decorated with lysine side chain active sites behaves as a heterogeneous organocatalyst. The pockets are...

scholarly journals One-Step Hydrothermal Synthesis of P25 @ Few Layered MoS2 Nanosheets toward Enhanced Bi-catalytic Activities: Photocatalysis and Electrocatalysis

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1636 ◽  
Author(s):  
Zhou ◽  
Zhang ◽  
Wang ◽  
Wang ◽  
Xu ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Transformation Efficiency ◽  
Hydrothermal Process ◽  
Mos2 Nanosheets ◽  
Sunlight Irradiation ◽  
Catalytic Activities ◽  
One Step ◽  
Layered Mos2

P25 loaded few layered molybdenum disulfide (MoS2) nanosheets (P25@MoS2) are successfully synthesized through a facile one-step hydrothermal process. The bi-catalytic activities, i.e., photocatalytic and electrocatalytic activities, of the as-prepared nanomaterials have been investigated. For the as-prepared products, the photocatalytic performances were investigated by degrading simulated pollutant under sunlight irradiation, and the hydrogen evolution reaction evaluated the electrocatalytic performances. The results indicate that P25@MoS2 possesses excellent activities in both photocatalysis and electrocatalysis. The presence of MoS2 broadens the light absorption range of P25 and improves the separation and transformation efficiency of photogenerated carriers, thus improving its photocatalytic performance. The existence of P25 inhibits the aggregation of MoS2 to form more dispersed MoS2 nanosheets with only few layers increasing its active sites. Thereby, the electrocatalytic performance is heightened. The excellent multifunction makes the as-prepared P25@MoS2 a promising material in the fields of environment and energy.

Controllable synthesis of Ni nanotube arrays and their structure-dependent catalytic activity toward dye degradation

CrystEngComm ◽  
2014 ◽  
Vol 16 (21) ◽  
pp. 4406-4413 ◽  
Author(s):  
Xiang-Zi Li ◽  
Kong-Lin Wu ◽  
Yin Ye ◽  
Xian-Wen Wei
Keyword(s):  
Catalytic Activity ◽  
Catalytic Properties ◽  
Dye Degradation ◽  
Nanotube Arrays ◽  
Nanorod Arrays ◽  
Growth Mechanisms ◽  
Controllable Synthesis ◽  
Catalytic Activities ◽  
One Step ◽  
The Relationship

Ni nanotube (nanorod) arrays are controllably fabricated by a one-step approach, the GDDATG and DDCG growth mechanisms are introduced. The Ni nanostructures present higher catalytic activities for dye degradation, the relationship between structures and catalytic properties is also studied.

scholarly journals Effect of Na2O Doping on the Surface and Catalytic Properties of the Mn2O3/Al2O3 System

1995 ◽  
Vol 12 (2) ◽  
pp. 119-128 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
S. Hammad
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Catalytic Properties ◽  
Xrd Analysis ◽  
Manganese Carbonate ◽  
Oxidation Of Co ◽  
Mechanical Mixing ◽  
Catalytic Activities ◽  
Specific Catalytic Activity ◽  
Catalytically Active

Manganese/aluminium mixed oxide solids having the formula 0.2MnCO3/Al2O3 were prepared by mechanical mixing of a known weight of finely powdered manganese carbonate and aluminium hydroxide. The solids obtained were treated with NaNO3 (0.75–6 mol%) solution and dried at 110°C, then calcined in air at 500°C and 800°C for 6 h. The phases produced were identified by XRD analysis. The surface properties (SBET, Vp and r̄) of the pure and doped solids were studied by using N2 adsorption at – 196°C and their catalytic activities were determined by studying the oxidation of CO by O2at 125–300°C. The results obtained reveal that pure and doped mixed solids preheated in air at 500°C and 800°C consist of Mn2O3 (partridgite) and a poorly crystalline γ-alumina. Doping with sodium oxide at 500°C and 800°C resulted in a small decrease (14–19%) in the SBET value of the treated solids. However, this treatment brought about a significant modification in the catalytic activity of the doped solids. Doping with 0.75% Na2O at 500°C led to an increase of about 30–50% in the specific catalytic activity which was found to decrease on increasing the percentage of Na2O above this limit, falling to values smaller than that measured for the undoped catalyst. Doping at 800°C led to a progressive decrease in the activity of the treated solid to an extent proportional to the amount of dopant present. The doping process at 500°C and 800°C did not modify the mechanism of the catalytic reaction but altered the number of catalytically-active sites contributing in the catalysis of CO oxidation by O2 without changing their energetic nature.

scholarly journals Enhanced catalytic activity of Au core Pd shell Pt cluster trimetallic nanorods for CO2 reduction

RSC Advances ◽  
2019 ◽  
Vol 9 (18) ◽  
pp. 10168-10173 ◽  
Author(s):  
Lan-qi He ◽  
Hao Yang ◽  
Jia-jun Huang ◽  
Xi-hong Lu ◽  
Gao-Ren Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Co2 Reduction ◽  
Catalytic Activities ◽  
Pt Cluster

Au@Pd@Pt nanorods greatly enhance the catalytic activities for CO2 reduction because of Pd–Pt edge active sites as investigated by SERS.

Template-directed approach to two-dimensional molybdenum phosphide–carbon nanocomposites with high catalytic activities in the hydrogen evolution reaction

2016 ◽  
Vol 40 (7) ◽  
pp. 6015-6021 ◽  
Author(s):  
Zhaoquan Yao ◽  
Yuezeng Su ◽  
Chenbao Lu ◽  
Chongqing Yang ◽  
Zhixiao Xu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Catalytic Activity ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
High Catalytic Activity ◽  
Two Dimensional ◽  
Carbon Nanocomposites ◽  
Carbon Nanosheets ◽  
Catalytic Activities ◽  
Molybdenum Phosphide

MoP-embedded 2D N-doped porous carbon nanosheets, with excellent electrical conductivity and abundant active sites, achieved high catalytic activity in the HER.

scholarly journals Surface and Catalytic Properties of NiO and Fe2O3 Solids

1997 ◽  
Vol 15 (8) ◽  
pp. 593-607 ◽  
Author(s):  
A. Abd. El-Aal ◽  
A.M. Ghozza ◽  
G.A. El-Shobaky
Keyword(s):  
Catalytic Activity ◽  
Calcination Temperature ◽  
Active Sites ◽  
Pore Radius ◽  
Total Pore Volume ◽  
Surface Characteristics ◽  
Oxidation Of Co ◽  
Catalytic Activities ◽  
Catalytically Active ◽  
The Mean

The surface characteristics, viz., the specific surface area SBET, the total pore volume Vp and the mean pore radius r̄, of NiO and Fe2O3 were determined from N2 adsorption isotherms conducted at −196°C for the different adsorbents preheated in air at temperatures in the range 300–800°C. The catalytic activities exhibited in CO oxidation by O2 on the various solids were investigated at temperatures varying between 150°C and 400°C. The effect of heating the NiO and Fe2O3 solids in CO and O2 atmospheres at 175–275°C on their catalytic activities was also studied. The results showed that increasing the calcination temperature in the range 300–800°C resulted in a progressive decrease in the SBET value of NiO and Fe2O3. The computed values of the apparent activation energy for the sintering of the oxides were 71 and 92 kJ/mol, respectively. The sintering of NiO and Fe2O3 took place mainly via a particle adhesion mechanism. The catalytic activity of NiO decreased progressively on increasing its calcination temperature from 300°C to 800°C, due to a decrease in its SBET value and the progressive removal of excess O2 which was present as non-stoichiometric NiO. This treatment also decreased the catalytic activity of Fe2O3. The decrease was, however, more pronounced when the temperature increased from 300°C to 400°C which was a result of the crystallization of the ferric oxide into the α-Fe2O3 phase. An increase in the calcination temperature for both oxides from 300°C to 800°C did not modify the mechanism of oxidation of CO by O2 over the various solids but rather changed the concentration of catalytically active sites. Heating NiO and Fe2O3 in CO and O2 atmospheres at 175–275°C modified their catalytic activities, with Fe2O3 being influenced to a greater extent than NiO.

scholarly journals Increasing Silicon Concentration and Doping Heteroatom to Successfully Realize High HER Catalytic Activity in 2D Metal-Free BSin (n = 1-4) Structures: A First-Principles Study

2021 ◽  
Author(s):  
Cuimei Li ◽  
Guangtao Yu ◽  
Ying Li ◽  
wei Chen
Keyword(s):  
Catalytic Activity ◽  
First Principles ◽  
Active Sites ◽  
Low Cost ◽  
Atomic Ratio ◽  
Two Dimensional ◽  
Metal Free ◽  
Catalytic Activities ◽  
High Efficient ◽  
New Strategies

Abstract Under the DFT calculations, the graphene-like two-dimensional (2D) BSin (n = 1-4) nanostructures are stable in terms of energy, kinetics and thermal aspects, and can possess metallic conductivity, which are advantageous to their catalytic activities for hydrogen evolution reaction (HER). Our computed results reveal that they can uniformly exhibit high HER catalytic activity. With increasing the Si/B atomic ratio, higher HER activity can be achieved, due to the change from weak aromaticity to strong anti-aromaticity for the correlative BxSiy six-membered rings. Moreover, by doping P, S, Ge and C atoms with the different electronegativity, the HER activity of the studied systems can be further improved because the electron transfer induced by these dopants can effectively activates the relevant B and Si atoms. In addition, in view of more active sites, increasing the Si concentration can also generally increase the HER activity of doped systems. For all BSin systems studied, the Si-Si bridge sites or Si-sites can uniformly serve as the most active sites. This study not only represents the first application of 2D metal-free BSin in HER catalysis, but also provides new strategies for designing high-efficient and low-cost HER electrocatalysts based on Si/B or even other Si-containing materials.

Catalytic Behaviours of MCM41 with High Content of Copper in NO+CO Reaction

2011 ◽  
Vol 236-238 ◽  
pp. 1828-1831
Author(s):  
Sha Li ◽  
Yuan Yang ◽  
Ying Jie Zhang ◽  
Yan Kong
Keyword(s):  
Catalytic Activity ◽  
Copper Content ◽  
Active Sites ◽  
Space Velocity ◽  
Type Curves ◽  
Catalytic Activities ◽  
No Reduction By Co ◽  
Excellent Activity ◽  
High Copper Content ◽  
Higher Temperature

The influences of space velocity, temperature and copper content in Cu-MCM41 catalysts with high copper content up to 26.1wt.% on the catalytic activity in NO reduction by CO were investigated. Results indicated 1) the prepared materials exhibited excellent activity for NO+CO reaction, 2) the catalytic activities increased with the copper contents and NO can be fully converted to N2 for the catalyst containing 26.1wt.% Cu with the space velocity of 30,000ml•g-1•h-1 at 673K to 823K, 3) catalytic activities of the original catalysts with the temperature were volcano-type curves, however, it increased straightly with temperature over the catalysts after reacting at 723K for 1h, which might be attributed to the different active sites and different catalytic mechanisms of the catalysts at lower and higher temperature, 4) the catalytic activity did not decline after reacting at 723K for 20 h in a reactant gas mixture of 33,000 ppm NO and 66,000 ppm CO.

One-step solvothermal synthesis of Al-promoted Fe3O4 magnetic catalysts for the selective oxidation of benzyl alcohol to benzaldehyde with H2O2 in water

RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 101048-101060 ◽  
Author(s):  
Leisha Xiong ◽  
Rong Chen ◽  
Fengxi Chen
Keyword(s):  
Catalytic Activity ◽  
Synergistic Effect ◽  
Benzyl Alcohol ◽  
Selective Oxidation ◽  
Solvothermal Synthesis ◽  
Active Sites ◽  
Title Reaction ◽  
Oxidation Of Benzyl Alcohol ◽  
One Step

The in situ modification of Fe3O4 by aluminium introduced new active sites besides the primary iron sites. Their synergistic effect contributes to much better catalytic activity of Al-promoted Fe3O4 in the title reaction.

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