Silica-supported Cu–Pt bimetallic catalysts for liquid-phase diethyl oxalate hydrogenation

2018 ◽  
Vol 96 (4) ◽  
pp. 394-403 ◽  
Author(s):  
Wei Long ◽  
Pingle Liu ◽  
Yang Lv ◽  
Wei Xiong ◽  
Fang Hao ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Catalysts ◽  
Nitrogen Adsorption ◽  
Hydrogen Uptake ◽  
Copper Catalysts ◽  
Catalytic Performance ◽  
Diethyl Oxalate ◽  
Hydrogen Chemisorption ◽  
Adsorption Desorption

Silica-supported copper catalysts were prepared by different methods, and Cu/SiO2 prepared by the urea-assisted gel method was modified with co-catalyst platinum to obtain Cu-Pt/SiO2 bimetallic catalysts. The prepared catalysts were characterized by nitrogen adsorption–desorption, XRD, TEM, hydrogen chemisorption, ammonia gas chemisorption, and X-ray photoelectron spectroscopy. The characterization results show that the modification of platinum is helpful to the reduction and dispersion of copper species, which increase the hydrogen uptake quantity and metal surface area. The 30%Cu–3.0%Pt/SiO2-6 presents the best catalytic performance in liquid-phase diethyl oxalate hydrogenation; it gives 77.32% conversion of diethyl oxalate and 94.37% selectivity to the main products under 473 K and 3.0 MPa for 4 h. A possible reaction route was also proposed.

scholarly journals Synergy between Ni and Co Nanoparticles Supported on Carbon in Guaiacol Conversion

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2199
Author(s):  
Elodie Blanco ◽  
Ana Belen Dongil ◽  
Néstor Escalona
Keyword(s):  
Liquid Phase ◽  
Bimetallic Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
N2 Adsorption ◽  
Nickel Cobalt ◽  
Co Nanoparticles ◽  
Adsorption Desorption

Nickel-cobalt bimetallic catalysts supported on high surface area graphite with different Ni:Co ratios (3:1, 2:1 and 1:1) and the monometallic Ni and Co were prepared by wetness impregnation method. The catalysts were tested in hydrodeoxygenation (HDO) of guaiacol in the liquid phase at 50 bar of H2 and 300 °C. The materials were characterized by N2 adsorption–desorption, XRD, TEM/STEM, H2-TPR, and CO-chemisorption to assess their properties and correlate them with the catalytic results. The activity was higher on the bimetallic catalysts and followed the trend NiCo2:1/G ∼ NiCo3:1/G > NiCo1:1/G > Co/G > Ni/G. Also, selectivity results showed that Ni was more active in the hydrogenation favoring cyclohexanol production from phenol, while this was inhibited on the Co-containing catalysts. Hence, the results showed that synergy was created between Ni and Co and that their interaction, properties, and catalytic performance depend on the metals’ ratio.

SBA-15 Supported Bimetallic Catalysts for Enhancement Isomers Production During n-Heptane Decomposition

2014 ◽  
Vol 12 (1) ◽  
pp. 345-354 ◽  
Author(s):  
Talib M. Albayati ◽  
Aidan M. Doyle
Keyword(s):  
Electron Microscopy ◽  
Bimetallic Catalysts ◽  
Flow Reactor ◽  
Heterogeneous Reaction ◽  
Plug Flow ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Adsorption Desorption

Abstract Santa Barbara Amorphous (SBA)-15 supported 1% (Pt–Ni), 1% (Pt–Co) and 1% (Ni–Co) bimetallic catalysts in a heterogeneous reaction for enhancement hydroisomerization and hydrocracking production during reforming or decomposition of n-heptane. The structural and textural features of the nanoporous silicas, both with and without encapsulated nanoparticles, were characterized using small-angle X-ray diffraction, scanning electron microscopy, EDAX, nitrogen adsorption–desorption porosimetry (Brunauer–Emmett–Teller) surface area analysis, Fourier-transform infrared spectroscopy and transmission electron microscopy. The catalytic performance was evaluated at 250–400°C under atmospheric pressure in a plug-flow reactor in a catalyst testing rig under tightly controlled conditions of temperature, reactant flow rate and pressure. The species leaving the reactor were analysed by Gas Chromatography. The results show that 1% (Pt–Ni)/SBA-15, 1% (Pt–Co)/SBA-15 and 1% (Ni–Co)/SBA-15 had a high activity for conversion of n-heptane (around 85%). The selectivity of isomerization is not high, so further studies have to be carried out in the future.

scholarly journals Pore Modification and Phosphorus Doping Effect on Phosphoric Acid-Activated Fe-N-C for Alkaline Oxygen Reduction Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1519
Author(s):  
Jong Gyeong Kim ◽  
Sunghoon Han ◽  
Chanho Pak
Keyword(s):  
Phosphoric Acid ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Electronic States ◽  
Nitrogen Adsorption ◽  
Reduction Reaction ◽  
Phosphorus Doping ◽  
X Ray ◽  
Precious Metal Catalysts ◽  
Adsorption Desorption

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

scholarly journals Synthesis of DME by CO2 hydrogenation over La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts

2017 ◽  
Vol 23 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Yajing Zhang ◽  
Yu Zhang ◽  
Fu Ding ◽  
Kangjun Wang ◽  
Wang Xiaolei ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Direct Synthesis ◽  
Catalytic Performance ◽  
Co2 Hydrogenation ◽  
Precipitation Method ◽  
X Ray ◽  
Temperature Programmed ◽  
And Performance ◽  
Co Precipitation ◽  
Adsorption Desorption

A series of La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts were prepared by an oxalate co-precipitation method. The catalysts were fully characterized by X-ray diffraction (XRD), N2 adsorption-desorption, hydrogen temperature pro-grammed reduction (H2-TPR), ammonia temperature programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy (XPS) techniques. The effect of the La2O3 content on the structure and performance of the catalysts was thoroughly investigated. The catalysts were evaluated for the direct synthesis of dimethyl ether (DME) from CO2 hydrogenation. The results displayed that La2O3 addition enhanced catalytic performance, and the maximal CO2 conversion (34.3%) and DME selectivity (57.3%) were obtained over the catalyst with 1% La2O3, which due to the smaller size of Cu species and a larger ratio of Cu+/Cu.

SYNTHESIS, CHARACTERIZATION AND THE APPLICABILITY OF β-CYCLODEXTRINS FUNCTIONALIZED MESOPOROUS SBA-15 MOLECULAR SIEVES

NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350050
Author(s):  
MIN GUAN ◽  
HAI-PENG BI ◽  
ZUYUAN WANG ◽  
SHAOHUA BU ◽  
LING HUANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Capacities ◽  
Transmission Electron ◽  
Potential Applications ◽  
Adsorption Desorption

Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.

scholarly journals APPLICABILITY OF THE LANGMUIR-HINSHELWOOD MODEL TO HYDROGENATION OF MONO - AND DISACCHARIDES ON THE Ru/HPS MN 100 CATALYST

2020 ◽  
pp. 29-40
Author(s):  
Максим Евгеньевич Григорьев ◽  
Олег Викторович Манаенков ◽  
Валентина Геннадьевна Матвеева ◽  
Роман Викторович Бровко
Keyword(s):  
Low Temperature ◽  
Specific Surface ◽  
Photoelectron Spectroscopy ◽  
Kinetic Studies ◽  
Nitrogen Adsorption ◽  
Chemical Study ◽  
Hydrogenation Reaction ◽  
Hydrogen Chemisorption ◽  
Entire Volume ◽  
Physical And Chemical

В данной статье представлены данные по физико-химическому исследованию гетерогенного рутений содержащего катализатора Ru/СПС MN 100. Представлена важность таких исследование для изучения каталитических реакций, для установления возможного механизма реакции гидрирования, а так же как дополнения при кинетических исследованиях. В статье катализатор исследован методом низкотемпературной адсорбции азота, хемосорбции водорода, просвечивающей электронной микроскопии (ПЭМ) и рентгенофотоэлектронной спектроскопии (РФЭС). Метод низкотемпературной адсорбции азота позволил установить, что катализатор характеризуется развитой внутренней удельной поверхностью (726 м/г по модели БЭТ) и характеризуется значительной мезопористостью, при этом наибольший диаметр пор составляет около 3.6 нм. Удельная площадь поверхности активного металла - Ru, по данным метода хемосорбции водорода, составляет 1 м/г. Рутений содержащие частицы распределены по всему объему носителя, при этом они способны образовывать небольшие агрегаты и характеризуются различной степенью кристалличности. Установлен элементный состав поверхности катализатора; Ru имеет различные степени окисления. На основании полученной ранее математическая модель процесса и проведенных физико-химических исследований катализатора предположена модель Ленгмюра-Хиншельвуда для описания механизма реакции жидкофазного каталитического гидрирования моно- и дисахаридов. This article presents data on the physical and chemical study of heterogeneous ruthenium-containing catalyst Ru/SPS MN 100. The importance of such studies for the study of catalytic reactions, for establishing the possible mechanism of the hydrogenation reaction, as well as additions in kinetic studies is presented. In this paper, the catalyst was studied by low-temperature nitrogen adsorption, hydrogen chemisorption, transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). The method of low-temperature nitrogen adsorption allowed us to establish that the catalyst is characterized by a developed internal specific surface (726 m/g according to the BET model) and is characterized by significant mesoporicity, with the largest pore diameter of about 3.6 nm. The specific surface area of the active metal - Ru, according to the method of hydrogen chemisorption, is 1 m/g. Ruthenium containing particles are distributed over the entire volume of the carrier, while they are able to form small aggregates and are characterized by different degrees of crystallinity. The elemental composition of the catalyst surface has been determined; Ru has different oxidation States. Based on the previously obtained mathematical model of the process and physical and chemical studies of the catalyst, the Langmuir-Hinshelwood model is proposed to describe the reaction mechanism of liquid-phase catalytic hydrogenation of mono - and disaccharides.

scholarly journals Preparation of GO/MIL-101(Fe,Cu) composite and its adsorption mechanisms for phosphate in aqueous solution

2021 ◽  
Author(s):  
You Wu ◽  
Zuannian Liu ◽  
Bakhtari Mohammad Fahim ◽  
Junnan Luo
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Adsorption Mechanism ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Adsorption Desorption

Abstract In this study, MIL-101(Fe), MIL-101(Fe,Cu), and Graphene Oxide (GO) /MIL-101(Fe,Cu) were synthesized to compose a novel sorbent. The adsorption properties of these three MOFs-based composites were compared toward the removal of phosphate. Furthermore, the influencing factors including reaction time, pH, temperature and initial concentration on the adsorption capacity of phosphate on these materials as well as the reusability of the material were discussed. The structure of fabricated materials and the removal mechanism of phosphate on the composite material were analyzed by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis and zeta potential. The results show that the maximum adsorption capacity of phosphate by the composite GO/MIL-101(Fe,Cu)-2% was 204.60 mg·g− 1, which is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe). likewise the specific surface area of GO/MIL-101(Fe,Cu)-2% is 778.11 m2/g is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe),which are 747.75 and 510.66m2/g respectively. The adsorption mechanism of phosphate is electrostatic attraction, form coordination bonds and hydrogen bonds. The fabricated material is a promising adsorbent for the removal of phosphate with good reusability.

scholarly journals A STUDY ON HYDROTHERMAL SYNTHESIS OF METAL–ORGANIC FRAMEWORK MIL-101

2017 ◽  
Vol 126 (1C) ◽  
pp. 21
Author(s):  
Võ Thị Thanh Châu ◽  
Hoàng Văn Đức
Keyword(s):  
Hydrothermal Synthesis ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Hydrothermal Process ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
Metal Organic ◽  
Adsorption Desorption ◽  
Organic Framework

<p>In the present paper, a synthesis of MIL-101 by hydrothermal process was demonstrated. The obtained samples were characterized by powder X-ray diffraction (PXRD), transmission electron microscope (TEM), nitrogen adsorption/desorption isotherms at 77K, X-ray photoelectron spectroscopy (XPS). The results showed that MIL-101 synthesized by optimal conditions exhibited high crystallinity and surface area. The obtained MIL-101 possesses high stability in water and several organic solvents.</p><p><strong>Keywords:</strong> MIL-101, hydrothermal synthesis, metal organic framework-101. </p>

scholarly journals Oxidative Coupling of Methane over Mn2O3-Na2WO4/SiC Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 363
Author(s):  
Jieun Kim ◽  
La-Hee Park ◽  
Jeong-Myeong Ha ◽  
Eun Duck Park
Keyword(s):  
Electron Microscopy ◽  
High Temperatures ◽  
Oxidative Coupling ◽  
Exothermic Reaction ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Oxidative Coupling Of Methane ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Adsorption Desorption

The oxidative coupling of methane (OCM) is operated at high temperatures and is a highly exothermic reaction; thus, hotspots form on the catalyst surface during reaction unless the produced heat is removed. It is crucial to control the heat formed because surface hotspots can degrade catalytic performance. Herein, we report the preparation of Mn2O3-Na2WO4/SiC catalysts using SiC, which has high thermal conductivity and good stability at high temperatures, and the catalyst was applied to the OCM. Two Mn2O3-Na2WO4/SiC catalysts were prepared by wet-impregnation on SiC supports having different particle sizes. For comparison, the Mn2O3-Na2WO4/SiO2 catalyst was also prepared by the same method. The catalysts were analyzed by nitrogen adsorption–desorption, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The transformation of SiC into α-cristobalite was observed for the Mn2O3-Na2WO4/SiC catalysts. Because SiC was completely converted into α-cristobalite for the nano-sized SiC-supported Mn2O3-Na2WO4 catalyst, the catalytic performance for the OCM reaction of Mn2O3-Na2WO4/n-SiC was similar to that of Mn2O3-Na2WO4/SiO2. However, only the surface layer of SiC was transformed into α-cristobalite for the micro-sized SiC (m-SiC) in Mn2O3-Na2WO4/m-SiC, resulting in a SiC@α-cristobalite core–shell structure. The Mn2O3-Na2WO4/m-SiC showed higher methane conversion and C2+ yield at 800 and 850 °C than Mn2O3-Na2WO4/SiO2.

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