Characterization and catalytic activity of nickel-zeolite catalysts. II. Effects of hydroxyl groups on reduction of nickel ions in mordenites

AbstractZeolite morphology is crucial in determining their catalytic activity, selectivity and stability, but quantitative descriptors of such a morphology effect are challenging to define. Here we introduce a descriptor that accounts for the morphology effect in the catalytic performances of H-ZSM-5 zeolite for C4 olefin catalytic cracking. A series of H-ZSM-5 zeolites with similar sheet-like morphology but different c-axis lengths were synthesized. We found that the catalytic activity and stability is improved in samples with longer c-axis. Combining time-resolved in-situ FT-IR spectroscopy with molecular dynamics simulations, we show that the difference in catalytic performance can be attributed to the anisotropy of the intracrystalline diffusive propensity of the olefins in different channels. Our descriptor offers mechanistic insight for the design of highly effective zeolite catalysts for olefin cracking.

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

Advances in Manufacturing ◽

10.1007/s40436-020-00321-2 ◽

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.

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

Chem ◽

10.1016/j.chempr.2018.01.019 ◽

2018 ◽

Vol 4 (3) ◽

pp. 613-625 ◽

Cited By ~ 43

Author(s):

Yuhan Peng ◽

Liangbing Wang ◽

Qiquan Luo ◽

Yun Cao ◽

Yizhou Dai ◽

...

Keyword(s):

Catalytic Activity ◽

Molecular Level ◽

Co2 Hydrogenation ◽

Hydroxyl Groups ◽

Insight Into

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

Catalysts ◽

10.3390/catal11091114 ◽

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.

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The Exchange Reaction of Deuterium with the Hydroxyl Groups of Zeolite Catalysts

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.45.366 ◽

1972 ◽

Vol 45 (2) ◽

pp. 366-370 ◽

Cited By ~ 8

Author(s):

Toshinobu Imanaka ◽

Yasuaki Okamoto ◽

Kazunori Takahata ◽

Shiichiro Teranishi

Keyword(s):

Exchange Reaction ◽

Zeolite Catalysts ◽

Hydroxyl Groups

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

Functional Materials Letters ◽

10.1142/s1793604716420091 ◽

2016 ◽

Vol 09 (06) ◽

pp. 1642009 ◽

Cited By ~ 4

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.

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Intermediate-crystallization promoted catalytic activity of titanosilicate zeolites

Journal of Materials Chemistry A ◽

10.1039/c8ta01960f ◽

2018 ◽

Vol 6 (18) ◽

pp. 8757-8762 ◽

Cited By ~ 28

Author(s):

Risheng Bai ◽

Qiming Sun ◽

Yue Song ◽

Ning Wang ◽

Tianjun Zhang ◽

...

Keyword(s):

Catalytic Activity ◽

Oxidative Desulfurization ◽

Zeolite Catalysts ◽

Crystallization Time ◽

Seeding Method

Crystallization time-modulated catalytic activity for oxidative desulfurization has been demonstrated over titanosilicate zeolite catalysts prepared by a seeding method.

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