scholarly journals Selective C–C Bond Cleavage in Diols and Lignin Models: High-Throughput Screening of Metal Oxide-Anchored Vanadium in Mesoporous Silica

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 901
Author(s):  
Xinnan Lu ◽  
Roxanne Clément ◽  
Yong Lu ◽  
Belén Albela ◽  
R. Tom Baker ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
High Throughput Screening ◽  
Active Sites ◽  
Bond Cleavage ◽  
Synthesis Method ◽  
Enabling Technology ◽  
Heterogeneous Oxidation ◽  
One Pot ◽  
Heterogeneous Catalytic ◽  
Platform Chemicals

The development of selective and robust heterogeneous oxidation catalysts is an enabling technology for conversion of biomass-derived platform chemicals. Vanadium active sites were incorporated into the structure of mesoporous silica via an ultra-fast, one-pot synthesis method based on microwave-assisted heating. In addition, Al/Ti/Zr/Ce anchoring ions were introduced in order to minimize vanadium leaching and better control its dispersion. The supported V-(Al/Ti/Zr/Ce)-MCM-41 composite materials were assessed as catalysts for aerobic C–C bond cleavage of simple models for lignin (1,2-diphenyl-2-methoxyethanol) and sugar-derived polyalcohols (meso-hydrobenzoin). The TiIV ions proved to be the best anchors to prevent V leaching, while AlIII and ZrIV ions were the best to improve selective conversion of the substrates. The active sites in these catalysts are shown to be 2D VOx layers stabilized on the anchors. In a screen of twelve solvents, weakly polar solvents like toluene were found to be most suitable for this reaction, as was environmentally friendly ethyl acetate. The above properties, together with the high selectivity for C–C bond cleavage, advocate for a heterogeneous catalytic pathway, intrinsically different from that reported previously for molecular oxovanadium (V) catalysts.

Ti-POSS covalently immobilized onto mesoporous silica: A model for active sites in heterogeneous catalytic epoxidation

2012 ◽  
Vol 380 ◽  
pp. 244-251 ◽  
Author(s):  
Fabio Carniato ◽  
Chiara Bisio ◽  
Laura Sordelli ◽  
Elena Gavrilova ◽  
Matteo Guidotti
Keyword(s):  
Mesoporous Silica ◽  
Active Sites ◽  
Heterogeneous Catalytic ◽  
Catalytic Epoxidation

Synthesis of SBA-15 encapsulated ammonium molybdophosphate using Qaidam natural clay and its use in cesium ion adsorption

RSC Advances ◽  
2015 ◽  
Vol 5 (45) ◽  
pp. 35453-35460 ◽  
Author(s):  
Chunyan Sun ◽  
Feng Zhang ◽  
Shengfang Li ◽  
Fangqin Cheng
Keyword(s):  
Mesoporous Silica ◽  
Qaidam Basin ◽  
Synthesis Method ◽  
Low Grade ◽  
Ion Adsorption ◽  
Natural Clay ◽  
One Pot ◽  
Hexagonal Mesoporous Silica ◽  
Ammonium Molybdophosphate ◽  
Cesium Ion

The ordered hexagonal mesoporous silica (SBA-15) encapsulated ammonium molybdophosphate (AMP) was successfully synthesized using low-grade natural clay from Qaidam Basin as silica and aluminum source, through a one-pot synthesis method.

Study on the selective oxidation of methane over highly dispersed molybdenum-incorporated KIT-6 catalysts

2021 ◽  
Author(s):  
Pei Chen ◽  
Zean Xie ◽  
Zhen Zhao ◽  
Jianmei Li ◽  
Bonan Liu ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Mesoporous Silica ◽  
Selective Oxidation ◽  
Synthesis Method ◽  
One Pot ◽  
Oxidation Of Methane ◽  
Highly Dispersed

A series of molybdenum-incorporated mesoporous silica (Mo-KIT-6) catalysts were successfully synthesized by a one-pot hydrothermal synthesis method and were applied in the selective oxidation of methane to formaldehyde using oxygen...

scholarly journals Highly Porous Au–Pt Bimetallic Urchin-Like Nanocrystals for Efficient Electrochemical Methanol Oxidation

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 112
Author(s):  
Heon Chul Kim ◽  
Jong Wook Hong
Keyword(s):  
Methanol Oxidation ◽  
Active Sites ◽  
Synthesis Method ◽  
High Porosity ◽  
One Pot ◽  
Wet Chemical Synthesis ◽  
Bimetallic Nanocrystals ◽  
Wet Chemical ◽  
Surface Active ◽  
Highly Porous

Highly porous Au–Pt urchin-like bimetallic nanocrystals have been prepared by a one-pot wet-chemical synthesis method. The porosity of urchin-like bimetallic nanocrystals was controlled by amounts of hydrazine used as reductant. The prepared highly porous Au-Pt urchin-like nanocrystals were superior catalysts of electrochemical methanol oxidation due to high porosity and surface active sites by their unique morphology. This approach will pave the way for the design of bimetallic porous materials with unprecedented functions.

Mg and Al dual-metal functionalized mesoporous carbon as highly efficient heterogeneous catalysts for synthesis of ethyl methyl carbonate

2021 ◽  
Author(s):  
Jinghui Shi ◽  
He Wang ◽  
Yanan Lin ◽  
Yunzuo Cui ◽  
Xiangxin Xue ◽  
...  
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Carbon Materials ◽  
Synthesis Method ◽  
One Pot ◽  
Ethyl Methyl ◽  
Ethyl Methyl Carbonate ◽  
Ordered Mesoporous ◽  
Methyl Carbonate ◽  
Dual Metal

Mg and Al dual-metal functionalized nanoscale porous carbon materials (MgAl@NC) with highly ordered mesoporous structures and mixed active sites were successfully prepared using a simple one-pot synthesis method. The catalytic...

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

scholarly journals Spinel of Nickel-Cobalt Oxide with Rod-Like Architecture as Electrocatalyst for Oxygen Evolution Reaction

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3918
Author(s):  
Anna Dymerska ◽  
Wojciech Kukułka ◽  
Marcin Biegun ◽  
Ewa Mijowska
Keyword(s):  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Solvothermal Reaction ◽  
Step Method ◽  
One Pot ◽  
Widespread Application ◽  
Nickel Cobalt ◽  
Slow Kinetics ◽  
Nickel Cobalt Oxide

The renewable energy technologies require electrocatalysts for reactions, such as the oxygen and/or hydrogen evolution reaction (OER/HER). They are complex electrochemical reactions that take place through the direct transfer of electrons. However, mostly they have high over-potentials and slow kinetics, that is why they require electrocatalysts to lower the over-potential of the reactions and enhance the reaction rate. The commercially used catalysts (e.g., ruthenium nanoparticles—Ru, iridium nanoparticles—Ir, and their oxides: RuO2, IrO2, platinum—Pt) contain metals that have poor stability, and are not economically worthwhile for widespread application. Here, we propose the spinel structure of nickel-cobalt oxide (NiCo2O4) fabricated to serve as electrocatalyst for OER. These structures were obtained by a facile two-step method: (1) One-pot solvothermal reaction and subsequently (2) pyrolysis or carbonization, respectively. This material exhibits novel rod-like morphology formed by tiny spheres. The presence of transition metal particles such as Co and Ni due to their conductivity and electron configurations provides a great number of active sites, which brings superior electrochemical performance in oxygen evolution and good stability in long-term tests. Therefore, it is believed that we propose interesting low-cost material that can act as a super stable catalyst in OER.

Thermally stable amine-functionalized silica sorbents using one-pot synthesis method for CO2 capture at low temperature

2020 ◽  
Vol 37 (12) ◽  
pp. 2317-2325
Author(s):  
Seong Bin Jo ◽  
Ho Jin Chae ◽  
Tae Young Kim ◽  
Jeom-In Baek ◽  
Dhanusuraman Ragupathy ◽  
...  
Keyword(s):  
Low Temperature ◽  
Co2 Capture ◽  
Synthesis Method ◽  
Functionalized Silica ◽  
Thermally Stable ◽  
One Pot ◽  
One Pot Synthesis ◽  
Amine Functionalized

scholarly journals Efficient Adsorption of Methylene Blue by Porous Biochar Derived from Soybean Dreg Using a One-Pot Synthesis Method

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 661
Author(s):  
Zhiwei Ying ◽  
Xinwei Chen ◽  
He Li ◽  
Xinqi Liu ◽  
Chi Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
Urban Pollution ◽  
Maximum Adsorption Capacity ◽  
One Pot ◽  
Average Pore ◽  
X Ray ◽  
Isotherm Equation

Soybean dreg is a by-product of soybean products production, with a large consumption in China. Low utilization value leads to random discarding, which is one of the important sources of urban pollution. In this work, porous biochar was synthesized using a one-pot method and potassium bicarbonate (KHCO3) with low-cost soybean dreg (SD) powder as the carbon precursor to investigating the adsorption of methylene blue (MB). The prepared samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analyzer (EA), Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), Raman spectroscopy (Raman), Fourier transform infrared spectrometer (FTIR), and X-ray photoelectron spectroscopy (XPS). The obtained SDB-K-3 showed a high specific surface area of 1620 m2 g−1, a large pore volume of 0.7509 cm3 g−1, and an average pore diameter of 1.859 nm. The results indicated that the maximum adsorption capacity of SDB-K-3 to MB could reach 1273.51 mg g−1 at 318 K. The kinetic data were most consistent with the pseudo-second-order model and the adsorption behavior was more suitable for the Langmuir isotherm equation. This study demonstrated that the porous biochar adsorbent can be prepared from soybean dreg by high value utilization, and it could hold significant potential for dye wastewater treatment in the future.

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