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

The promoted active sites for the CO2 reduction reaction on Ni-LaOx/oCNT consist of LaOx species on the surface of Ni NPs and are responsible for the highest TOF rate (51.8 × 10−3 s−1) of CO2 conversion with 100% methane selectivity at 240 °C.

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

Adsorption Science & Technology ◽

10.1177/026361749501200204 ◽

1995 ◽

Vol 12 (2) ◽

pp. 119-128 ◽

Cited By ~ 10

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.

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Photoelectrochemical Reduction of CO2 to Syngas by Reduced Ag Catalysts on Si Photocathodes

Applied Sciences ◽

10.3390/app10103487 ◽

2020 ◽

Vol 10 (10) ◽

pp. 3487 ◽

Cited By ~ 1

Author(s):

Changyeon Kim ◽

Seokhoon Choi ◽

Min-Ju Choi ◽

Sol A Lee ◽

Sang Hyun Ahn ◽

...

Keyword(s):

Catalytic Activity ◽

Active Sites ◽

Co2 Reduction ◽

Reduction Reaction ◽

Hydrogen Electrode ◽

Faradaic Efficiency ◽

Onset Potential ◽

Reduction Of Co2 ◽

Co2 Reduction Reaction ◽

Ag Catalysts

The photoelectrochemical reduction of CO2 to syngas that is used for many practical applications has been emerging as a promising technique to relieve the increase of CO2 in the atmosphere. Si has been considered to be one of the most promising materials for photoelectrodes, but the integration of electrocatalysts is essential for the photoelectrochemical reduction of CO2 using Si. We report an enhancement of catalytic activity for CO2 reduction reaction by Ag catalysts of tuned morphology, active sites, and electronic structure through reducing anodic treatment. Our proposed photocathode structure, a SiO2 patterned p-Si photocathode with these reduced Ag catalysts, that was fabricated using electron-beam deposition and electrodeposition methods, provides a low onset-potential of −0.16 V vs. the reversible hydrogen electrode (RHE), a large saturated photocurrent density of −9 mA/cm2 at −1.23 V vs. RHE, and faradaic efficiency for CO of 47% at −0.6 V vs. RHE. This photocathode can produce syngas in the ratio from 1:1 to 1:3, which is an appropriate proportion for practical application. This work presents a new approach for designing photocathodes with a balanced catalytic activity and light absorption to improve the photoelectrochemical application for not only CO2 reduction reaction, but also water splitting or N2 reduction reaction.

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

New Journal of Chemistry ◽

10.1039/c5nj03440j ◽

2016 ◽

Vol 40 (7) ◽

pp. 6015-6021 ◽

Cited By ~ 20

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.

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Surface and Catalytic Properties of NiO and Fe2O3 Solids

Adsorption Science & Technology ◽

10.1177/026361749701500805 ◽

1997 ◽

Vol 15 (8) ◽

pp. 593-607 ◽

Cited By ~ 2

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.

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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

Journal of The Electrochemical Society ◽

10.1149/1945-7111/ac4458 ◽

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.236-238.1828 ◽

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.

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

Catalysts ◽

10.3390/catal9050408 ◽

2019 ◽

Vol 9 (5) ◽

pp. 408 ◽

Cited By ~ 9

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.

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The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

Catalysis Science & Technology ◽

10.1039/c8cy02291g ◽

2019 ◽

Vol 9 (3) ◽

pp. 811-821 ◽

Cited By ~ 7

Author(s):

Zhao-Meng Wang ◽

Li-Juan Liu ◽

Bo Xiang ◽

Yue Wang ◽

Ya-Jing Lyu ◽

...

Keyword(s):

Catalytic Activity ◽

Active Sites ◽

Aerobic Oxidation ◽

Catalytic Performance ◽

Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

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Polymer structure and catalytic activity of ion exchangers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811577 ◽

1981 ◽

Vol 46 (7) ◽

pp. 1577-1587 ◽

Cited By ~ 8

Author(s):

Karel Jeřábek

Keyword(s):

Catalytic Activity ◽

Ethyl Acetate ◽

Active Sites ◽

Crosslinking Agent ◽

Reaction Medium ◽

Polymer Structure ◽

Local Concentration ◽

Ion Exchangers ◽

Styrene Divinylbenzene ◽

Kinetics Of

Catalytic activity of ion exchangers prepared by partial sulphonation of styrene-divinylbenzene copolymers in reesterifications of ethyl acetate by methanol and propanol, hydrolysis of ethyl acetate and in synthesis of bisphenol A has been compared with data on polymer structure of these catalysts and with distribution of the crosslinking agent, divinylbenzene, calculated from literature data on kinetics of copolymerisation of styrene with divinylbenzene. It was found that the polymer structure of ion exchangers influences catalytic activity predominantly by changing the local concentration of acid active sites. The results obtained indicated that the effect of transport phenomena on the rate of catalytic reactions does not depend on the degree of swelling of the ion exchangers in reaction medium but it is mainly dependent on the relative affinity of reaction components to the acid groups or to the polymer skeleton.

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