Structural and Oxidative Properties of Manganese Incorporated Mesostructure Silica for Methane Oxidation

Manganese catalysts containing templated mesostructured porous silica were prepared using different methods of preparation, namely, the direct hydrothermal (DHT), solid-state ion exchange (SSI), template ion exchange (TIE), and impregnation (Imp) methods. The physical-chemical properties of materials were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, FT-IR, TEM, EDX, UV-Vis, EPR, and H2 TPR techniques. The results of this study indicate that the obtained catalysts retained their hexagonal mesopore structure after introducing Mn into MCM-41. On the contrary, the crystalline phase of manganese oxide was stabilized on the external surface and inside the mesoporosity of the MCM-41 and seems to be dependent on the synthesis method used. Catalytic performances of synthesized materials were then investigated in methane oxidation at atmospheric pressure. The results showed that the metal loading and catalysts synthesis procedure influence the catalytic performance of the obtained materials. Moreover, the activity of the catalyst depends on the crystalline phase and particularly on the environment of the active phase.

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Facile One-Step Dialysis Strategy for Preparation of Porous Silica Nanoparticles with Rough Surface

NANO ◽

10.1142/s1793292020500381 ◽

2020 ◽

Vol 15 (03) ◽

pp. 2050038

Author(s):

Zhe Chen ◽

Jiaqiong Xu ◽

Xuechen Xiang ◽

Dongfang Ren ◽

Ning Chen ◽

...

Keyword(s):

Silica Nanoparticles ◽

Rough Surface ◽

Mesoporous Silica Nanoparticles ◽

Porous Silica ◽

Catalytic Performance ◽

Ammonia Solution ◽

Type Iv ◽

Organic Surfactant ◽

One Step ◽

Adsorption Desorption

In this study, porous silica nanoparticles were fabricated in the absence of organic surfactant template at room temperature by a facile one-step dialysis method. By using a dialysis system comprising an ammonia solution as the dialysate, a series of porous silica nanoparticles with a rough surface (e.g., raspberry-like) were obtained by the initiation of a homogeneous ternary tetraethylsilicate-water-ethanol system with different ammonia solution concentrations. The specific surface area and pore volume of porous nanoparticles were regulated by changing the dialysate concentrations. N2 adsorption–desorption measurements revealed that the porous silica nanoparticles owned both mesopores and micropores and exhibited a type IV isotherm, hence, these nanoparticles can be used as mesoporous silica nanoparticles (MSNs). The Au@MSN nanocomposite can be used as a catalyst for the typical reduction of 4-nitrophenol to 4-aminophenol by NaBH4 and exhibited excellent catalytic performance.

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Comparison of TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 Hybrid Catalysts in Characteristics and Photodegradation of Tetramethylammonium

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.93-94.22 ◽

2010 ◽

Vol 93-94 ◽

pp. 22-26 ◽

Cited By ~ 1

Author(s):

Surachai Artkla ◽

Won Yong Choi ◽

Jatuporn Wittayakun

Keyword(s):

Irradiation Time ◽

Catalytic Performance ◽

X Ray Diffraction ◽

N2 Adsorption ◽

X Ray ◽

Transmission Electron ◽

Photocatalytic Activities ◽

Adsorption Desorption ◽

Two Hybrid ◽

Mcm 41

This work compared properties and catalytic performance of two hybrid photocatalysts, TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 prepared by loading nanoparticles of TiO2 (10 wt.%) on MCM-41 synthesized with rice husk silica and tetraethyl orthosilicate respectively. The supports and catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy and zeta potential. The photocatalytic activities of the TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 for the degradation of tetramethylammonium (TMA) in aqueous slurry were similar with a complete conversion after irradiation time of 90 min at pH 7.

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Synthesis of Al-Containing Mesoporous Molecular Sieves and their Catalytic Performance to Isomerization Reaction of Endo-Tetrahydrodicyclo-Pentadiene

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.234 ◽

2011 ◽

Vol 233-235 ◽

pp. 234-237 ◽

Cited By ~ 2

Author(s):

Sa Liu ◽

Jian Wei Guo ◽

Chu Fen Yang ◽

Long Huan Li ◽

Yi Hua Cui

Keyword(s):

Catalytic Activity ◽

Molecular Sieves ◽

Catalytic Performance ◽

Mesoporous Molecular Sieves ◽

Isomerization Reaction ◽

Inorganic Acid ◽

Ft Ir ◽

Desorption Isotherms ◽

Adsorption Desorption ◽

Mcm 41

Al-containing mesoporous molecular sieves(Al-MCM-41) were synthesized at ambient temperature. The structures of samples were characterized by XRD, N2-adsorption/desorption isotherms and FT-IR, etc. The evaluation results showed that Al-MCM-41 had higher catalytic activity for isomerization conversion of endo-tetrahydrodicyclo-pentadiene (endo-TCD) into exo-tetrahydrodicyclo-pentadiene (exo-TCD) and adamantane (AdH). Loading inorganic acid on the surface of Al-MCM-41 led increase of its catalytic activity and the yield of adamantane.

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Effect of the acidity of HZSM-5/MCM-41 hierarchical zeolite on its catalytic performance in supercritical catalytic cracking ofn-dodecane: experiments and mechanism

Catalysis Science & Technology ◽

10.1039/c8cy00908b ◽

2018 ◽

Vol 8 (16) ◽

pp. 4241-4256 ◽

Cited By ~ 9

Author(s):

Xiaochao Xian ◽

Chao Ran ◽

Peng Yang ◽

Yirong Chu ◽

Shuo Zhao ◽

...

Keyword(s):

Ion Exchange ◽

Catalytic Cracking ◽

Catalytic Performance ◽

Hierarchical Zeolite ◽

Mcm 41

Tuning the acidity of ZSM-5/MCM-41 hierarchical zeolite by ion exchange with NaCl can enhance its stability for supercritical catalytic cracking.

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Preparation and Characterization of Chabazite from Construction Waste and Application as an Adsorbent for Methylene Blue

Adsorption Science & Technology ◽

10.1155/2021/9994079 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Xue Song ◽

Yingming Zhang ◽

Xiangke Cui ◽

Fangfang Liu ◽

Hailiang Zhao

Keyword(s):

Methylene Blue ◽

Removal Rate ◽

Synthesis Method ◽

Chemical Properties ◽

Maximum Adsorption Capacity ◽

Building Projects ◽

Construction Waste ◽

Alkali Fusion ◽

Adsorption Desorption ◽

Physical And Chemical

Construction waste, produced from building projects, was utilized to prepare chabazite by alkali fusion hydrothermal synthesis method. The synthesized chabazite was used as an adsorbent for the removal of methylene blue (MB). XRD, FTIR, and N2 adsorption/desorption curves were adopted to describe the physical and chemical properties of the samples. The results show that the synthesized chabazite possesses crystalline structure, typical functional groups, and large specific surface area of 421.34 m2 g-1. Adsorption isotherms and kinetic curves show that the adsorption process follows the Langmuir model and pseudo-second-order kinetics model. The maximum adsorption capacity of MB on the synthesized chabazite reaches up to 129.18 mg g-1 at 298 K, which is about 16 times that of construction waste. The removal rate of MB reaches more than 90%, and the adsorbed amount is about 35 mg g-1 after 1 h at 298 K. Thermodynamic parameters, namely Δ H , Δ S , and Δ G of -12.83 kJ mol-1, -27.37 J mol-1 K-1, and -4.68 kJ mol-1 at 298 K, respectively, indicate that the adsorption of MB on the chabazite is physical, orderliness-tended, and spontaneous process. Moreover, the synthesized chabazite has a good property of regeneration and reuse. The results indicate that using construction waste to prepare chabazite in application as an adsorbent is feasible, which provides a novel and environment-friendly way for recycling construction waste.

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Synthesis of Ni-Modified ZSM-5 Zeolites and Their Catalytic Performance in n-Octane Hydroconversion

Frontiers in Chemistry ◽

10.3389/fchem.2020.586445 ◽

2020 ◽

Vol 8 ◽

Author(s):

Qiang Wei ◽

Pengfei Zhang ◽

Xiaodong Liu ◽

Wenbin Huang ◽

Xiayun Fan ◽

...

Keyword(s):

Supported Catalysts ◽

Synthesis Method ◽

Textural Properties ◽

Catalytic Performance ◽

Acid Sites ◽

Impregnation Method ◽

Isomerization Selectivity ◽

Nimo Catalysts ◽

Adsorption Desorption

Ni-modified ZSM-5 zeolites with different nickel contents were successfully prepared by the in situ synthesis method and the impregnation method. The synthesized samples were characterized by XRD, SEM, N2 adsorption–desorption isothermals, and Py-FTIR. The characterization results show that both the textural properties and crystallization of Ni-modified ZSM-5 zeolites were preserved well, and their acidic properties can be modulated after nickel modification. The corresponding NiMo catalysts supported on Ni-modified ZSM-5 zeolites were prepared by the incipient wetness co-impregnation method, and their catalytic performances were evaluated in n-octane hydroconversion. Compared to the those modified by the in situ synthesis method, ZSM-5 zeolite-supported catalysts modified by the impregnation method exhibit higher stability and higher isomerization selectivity. This is due to the synergistic effect between Brønsted acid sites and Lewis acid sites on the Ni-modified ZSM-5 zeolites, especially for the NiMo/1Ni-Z5 catalyst.

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On the Performance of Metal Supported Catalysts Prepared by Microemulsion: Sol Gel and Precipitation of the Support Precursor

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1276 ◽

2005 ◽

Vol 3 (1) ◽

Cited By ~ 1

Author(s):

Gustavo Pérez ◽

J. Luis Suaste ◽

César Barrales ◽

J. Antonio De los Reyes ◽

Juan Pérez-Sea ◽

...

Keyword(s):

Supported Catalysts ◽

Sol Gel ◽

Synthesis Method ◽

Active Phase ◽

Catalytic Performance ◽

Ammonium Bromide ◽

Microemulsion Method ◽

Structure Sensitive ◽

Cetyltrimethyl Ammonium

Ni/SiO2, NiMo/Al2O3 and CoMo/Al2O3 were prepared by microemulsion method. Precipitation and sol-gel of the support precursor allowed the synthesis of catalysts with differences in textural, structural and catalytic properties. The main difference between the precipitation and sol-gel microemulsion routes is the role of surfactant (Cetyltrimethyl Ammonium Bromide) in each synthesis method. The aggregation mechanism of support is modified by the synthesis route. There are differences in the catalytic performance of Ni/SiO2 microemulsion catalysts by the precipitation or sol-gel of support precursor. The hydrogenation of benzene, a low structure-sensitive reaction, showed that the precipitation 9%Ni/SiO2 microemulsion catalyst is more active than the sol-gel 9%Ni/SiO2 microemulsion catalyst. On other hand, these catalysts showed opposite result in the hydrogenation of C=C double bond of crotonaldehyde molecule. These results are indicative of the effects of nanostructured support and nanostructured active-phase in the hydrogenation activity. NiMo/Al2O3 and CoMo/Al2O3 catalysts prepared by sol-gel-microemulsion method were used in the hydrodesulphurization (HDS) of dibenzothiophene and 4,6-dimethyldibenzothiophene. The HDS activity was improved as a function of metal content and it motivates the study of NiMo and CoMo microemulsion catalysts with higher contents of metals to enhance the HDS of 4,6-dimethyldibenzothiophene.

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Synthesis and catalytic performance of MCM-41 modified with tetracarboxylphthalocyanine

Chemical Papers ◽

10.2478/s11696-012-0288-2 ◽

2013 ◽

Vol 67 (4) ◽

Author(s):

Ya-Ping Zhang ◽

Ke-Chuang Xue ◽

Wei-Ping Zhang ◽

Chao Song ◽

Rong-Lan Zhang ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalytic Performance ◽

Conversion Ratio ◽

X Ray Diffraction ◽

Amino Groups ◽

N2 Adsorption ◽

X Ray ◽

Adsorption Desorption ◽

Mcm 41 ◽

Scanning Electron

AbstractA series of tetracarboxylphthalocyanines (MPc(COOH)4, M = H, Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)) were anchored onto MCM-41 by the following procedures: functionalization of MCM-41 with (EtO)3SiCH2CH2CH2NH2 reacting with surface Si-OH, and anchoring MPc(COOH)4 onto MCM-41 with a substitution reaction between chloroformyl and amino groups. The samples were characterized by infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption, and X-ray photoelectron spectroscopy. Catalytic activity of oxidation was tested using solutions of ethanethiol in petroleum ether and thiophene in octane; CoPc-CONH-MCM-41 displayed the highest conversion ratio of 90.15 % and 93.79 %, respectively.

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Synthesis, Characterization and Catalytic Performance of Well-ordered Crystalline Heteroatom Mesoporous MCM-41

10.20944/preprints201612.0094.v1 ◽

2016 ◽

Author(s):

Jing Qin ◽

Baoshan Li

Keyword(s):

Electron Microscopy ◽

Crystalline Phase ◽

Metal Ion ◽

Mesoporous Structure ◽

Catalytic Performance ◽

Ionic Complex ◽

Cumene Cracking ◽

X Ray ◽

Surface Areas ◽

Mcm 41

The mesoporous heteroatom molecular sieve MCM-41 bulk crystals with the crystalline phase were synthesized via a one-step hydrothermal method using an ionic complex as template. The ionic complex template was formed by interaction between cetyltrimethylammonium ions and metal complex ion [M (EDTA)]2- (M=Co or Ni ). The materials were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, N2 adsorption–desorption isotherms, and X-ray absorption fine structure spectroscopy. The results showed that the materials possess a highly ordered mesoporous structure with the crystalline phase and possess high uniform ordered arrangement channels. The structure is in the vertical cross directions with a crystalline size of about 12 µm and high specific surface areas. The metal atoms were incorporated into the zeolite frameworks in the form of octahedral coordinate and have a uniform distribution in the materials. The amount of metal complexes formed by metal ion and EDTA is an essential factor for the formation of the vertical cross structure. Comparing to Si-MCM-41, the samples exhibited better conversion, higher selectivity for cumene cracking.

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