Molecular-Level Understanding of Hydroxyl Groups Boosted the Catalytic Activity of the CuZnAl Catalyst in the Conversion of Syngas to Ethanol

2019 ◽  
Vol 58 (42) ◽  
pp. 19421-19433
Author(s):  
Bing Bai ◽  
Hui Bai ◽  
Jianping Zuo ◽  
Qian-Fan Zhang ◽  
Haojie Cao ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Level ◽  
Hydroxyl Groups

scholarly journals Molecular-Level Insight into How Hydroxyl Groups Boost Catalytic Activity in CO2 Hydrogenation into Methanol

Chem ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 613-625 ◽  
Author(s):  
Yuhan Peng ◽  
Liangbing Wang ◽  
Qiquan Luo ◽  
Yun Cao ◽  
Yizhou Dai ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Level ◽  
Co2 Hydrogenation ◽  
Hydroxyl Groups ◽  
Insight Into

scholarly journals High catalytic activity for formaldehyde oxidation of an interconnected network structure composed of δ-MnO2 nanosheets and γ-MnOOH nanowires

2020 ◽  
Vol 8 (4) ◽  
pp. 429-439
Author(s):  
Ying Tao ◽  
Rong Li ◽  
Ai-Bin Huang ◽  
Yi-Ning Ma ◽  
Shi-Dong Ji ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Network Structure ◽  
Manganese Oxides ◽  
Active Oxygen Species ◽  
Low Cost ◽  
High Dispersion ◽  
Hydroxyl Groups ◽  
High Catalytic Activity ◽  
Interconnected Network ◽  
Surface Hydroxyl

AbstractAmong the transition metal oxide catalysts, manganese oxides have great potential for formaldehyde (HCHO) oxidation at ambient temperature because of their high activity, nontoxicity, low cost, and polybasic morphologies. In this work, a MnO2-based catalyst (M-MnO2) with an interconnected network structure was successfully synthesized by a one-step hydrothermal method. The M-MnO2 catalyst was composed of the main catalytic agent, δ-MnO2 nanosheets, dispersed in a nonactive framework material of γ-MnOOH nanowires. The catalytic activity of M-MnO2 for HCHO oxidation at room temperature was much higher than that of the pure δ-MnO2 nanosheets. This is attributed to the special interconnected network structure. The special interconnected network structure has high dispersion and specific surface area, which can provide more surface active oxygen species and higher surface hydroxyl groups to realize rapid decomposition of HCHO.

Characterization and Catalytic Activity of Poly(4-Vinylpyridine-Co-Divinylbenzene)-Co2+ Complex

2005 ◽  
Vol 494 ◽  
pp. 363-368 ◽  
Author(s):  
D. Lončarević ◽  
Ž. Čupić
Keyword(s):  
Catalytic Activity ◽  
Molecular Level ◽  
Supported Catalysts ◽  
Lone Pair ◽  
Polymer Support ◽  
Polymeric Complex ◽  
Reaction Conditions ◽  
Pyridine Nitrogen ◽  
Nitrogen Lone Pair ◽  
Thermal Stability Of

Poly(4-vinylpyridine-co-divinylbenzene)-Co2+ was characterized using infrared spectroscopy (IR), thermogravimetric analysis (TG-DTA), N2-physisorption and polarography. Thermal analysis suggests sufficient thermal stability of the polymer support, under reaction conditions. From polarography measurements, the Co2+ content on polymer-supported catalysts is estimated and it was proved that no significant leaching occurred during the activity tests. At the molecular level, FTIR of P4VP-DVB-Co2+ reveals that the pyridine nitrogen lone pair coordinates to the metal center in the polymeric complex. The obtained P4VP-DVB-Co2+ catalysts performed interesting catalytic activity in reaction of the cyclohexane oxidation with air, indicating that increasing Co2+ content lowers the initiation temperature and raises the decomposition of cyclohexylhydroperoxide.

scholarly journals Understanding the Catalytic Activity of Microporous and Mesoporous Zeolites in Cracking by Experiments and Simulations

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1114
Author(s):  
Shih-Cheng Li ◽  
Yen-Chun Lin ◽  
Yi-Pei Li
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
Petrochemical Industry ◽  
Molecular Level ◽  
Shape Selectivity ◽  
Zeolite Catalysts ◽  
Hydrocarbon Cracking ◽  
Mesoporous Zeolites ◽  
Secondary Reactions ◽  
Pros And Cons

Porous zeolite catalysts have been widely used in the industry for the conversion of fuel-range molecules for decades. They have the advantages of higher surface area, better hydrothermal stability, and superior shape selectivity, which make them ideal catalysts for hydrocarbon cracking in the petrochemical industry. However, the catalytic activity and selectivity of zeolites for hydrocarbon cracking are significantly affected by the zeolite topology and composition. The aim of this review is to survey recent investigations on hydrocarbon cracking and secondary reactions in micro- and mesoporous zeolites, with the emphasis on the studies of the effects of different porous environments and active site structures on alkane adsorption and activation at the molecular level. The pros and cons of different computational methods used for zeolite simulations are also discussed in this review.

Hollow structured CoSn(OH)6-supported Pt for effective room-temperature oxidation of gaseous formaldehyde

2016 ◽  
Vol 09 (06) ◽  
pp. 1642009 ◽  
Author(s):  
Jing Zhou ◽  
Yong Zhao ◽  
Lifan Qin ◽  
Chen Zeng ◽  
Wei Xiao
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Room Temperature ◽  
Synergetic Effect ◽  
Hollow Structure ◽  
Pt Nanoparticles ◽  
Hydroxyl Groups ◽  
High Catalytic Activity ◽  
Temperature Oxidation ◽  
X Ray

Uniform CoSn(OH)6 hollow nanoboxes and the derivative with Pt loading (Pt/CoSn(OH)6) were herein synthesized and characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). SEM and TEM analyses showed that CoSn(OH)6 possessed mesoporous hollow structure and Pt nanoparticles with size of 2–8[Formula: see text]nm were uniformly dispersed on the surface of CoSn(OH)6 nanoboxes. The performances of the catalysts for the formaldehyde (HCHO) removal at room temperature were evaluated. These Pt/CoSn(OH)6 catalysts exhibited a remarkable catalytic activity as well as stability for room-temperature oxidative decomposition of gaseous HCHO, while the corresponding CoSn(OH)6 only showed adsorption. The synergetic effect between the highly dispersed Pt nanoparticles and the CoSn(OH)6 nanoboxes with mesoporous hollow structure, a large surface area and abundant surface hydroxyl groups is considered to be the main reason for the observed high catalytic activity of Pt/CoSn(OH)6.

scholarly journals Deciphering nanoconfinement effects on molecular orientation and reaction intermediate by single molecule imaging

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Bin Dong ◽  
Yuchen Pei ◽  
Nourhan Mansour ◽  
Xuemei Lu ◽  
Kai Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Single Molecule ◽  
Molecular Orientation ◽  
Rational Design ◽  
Molecular Level ◽  
Catalyst Activity ◽  
Molecular Transport ◽  
Nanoporous Structure ◽  
Core Shell ◽  
Single Molecule Studies

Abstract Nanoconfinement could dramatically change molecular transport and reaction kinetics in heterogeneous catalysis. Here we specifically design a core-shell nanocatalyst with aligned linear nanopores for single-molecule studies of the nanoconfinement effects. The quantitative single-molecule measurements reveal unusual lower adsorption strength and higher catalytic activity on the confined metal reaction centres within the nanoporous structure. More surprisingly, the nanoconfinement effects on enhanced catalytic activity are larger for catalysts with longer and narrower nanopores. Experimental evidences, including molecular orientation, activation energy, and intermediate reactive species, have been gathered to provide a molecular level explanation on how the nanoconfinement effects enhance the catalyst activity, which is essential for the rational design of highly-efficient catalysts.

Effect of hydrogen bonding on catalytic activity of some manganese porphyrins in epoxidation reactions

2011 ◽  
Vol 15 (03) ◽  
pp. 181-187 ◽  
Author(s):  
Tahereh Alemohammad ◽  
Nasser Safari ◽  
Samira Osati
Keyword(s):  
Hydrogen Bonding ◽  
Catalytic Activity ◽  
Axial Ligand ◽  
Hydroxyl Groups ◽  
Manganese Porphyrins ◽  
Bonding Effect ◽  
Meso Position ◽  
Hydrogen Bonding Effect ◽  
Mn Porphyrins ◽  
Effective Hydrogen

Mn (III)-tetra phenyl porphyrin-acetate (MnTPPOAc) and some kinds of meso-phenyl substituted porphyrins by hydroxyl groups and their Mn (III) complexes were synthesized. These Mn -porphyrins were used as catalyst in the epoxidation of various alkenes with tetra-n-butylammonium hydrogen monopersulfate (n- Bu4NHSO5 ) as oxidant and tetra-n-butylammonium acetate (n- Bu4NOAc ) as the axial ligand. The following order of catalytic activity was observed for cyclooctene: T(2,3-OHP)PMnOAc ≫ T(2,4,6-OHP)PMnOAc ≥ T(4-OHP)PMnOAc ≥ T(2,6-OHP)PMnOAc ≥ TPPMnOAc and T(2,3-OHP)PMnOAc ≫ TPPMnOAc > T(4-OHP)PMnOAc > T(2,4,6-OHP)PMnOAc > T(2,6-OHP)PMnOAc for other alkenes. Different activity and stability of the catalysts were interpreted based on the hydrogen bonding between hydroxyl groups with appropriate orientation on the meso-position of the phenyl groups and axial bases or oxidant. T(2,3-OHP)PMnOAc catalyst has shown optimal condition for effective hydrogen bonding. In the case of other catalysts, electronic and steric factors overcome the hydrogen bonding effect.

scholarly journals Modified powder activated carbon-catalyzed ozonation of humic acid: influences of chemical and textural properties

2018 ◽  
Vol 2017 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Jing Feng ◽  
Yang Yang ◽  
Honglin Chen ◽  
Xiaoming Zhang
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Humic Acid ◽  
Chemical Property ◽  
Radical Reaction ◽  
Lewis Base ◽  
Hydroxyl Groups ◽  
Free Radical Reaction ◽  
Surface Chemical ◽  
Surface Chemical Property

Abstract A modification method that combines thermal and oxidation treatments was used to improve catalytic activity of activated carbon (AC) which catalyzed ozonation of the aquatic contaminant humic acid (HA). As a consequence of modifying virgin AC, modified AC (ACN2O2N2) had good catalytic performance for ozonation of HA. Apparent first-order rate constants (kapp) were ACN2O2N2 (7.88 × 10−3 s−1) > virgin AC (3.28 × 10−3 s−1). This change was discussed in terms of three factors: textural property, graphitization degree, and surface chemical property. From analysis results, it was deduced that the surface chemical property (the concentration of surface groups) was the main factor that influenced catalytic activity. An increase in the concentration of hydroxyl groups on AC enhanced catalytic activity of AC in ozonation of HA. Effects of phosphate (both a ligand and a strong Lewis base) further confirmed that Lewis acid sites (hydroxyl groups) were the active centers for free radical reaction in catalytic ozonation of AC.

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