Effect of the Metal Deposition Order on Structural, Electronic and Catalytic Properties of TiO2-Supported Bimetallic Au-Ag Catalysts in 1-Octanol Selective Oxidation

Au and Ag were deposited on TiO2 modified with Ce, La, Fe or Mg in order to obtain bimetallic catalysts to be used for liquid-phase oxidation of 1-octanol. The effects of the deposition order of gold and silver, and the nature of the support modifying additives and redox pretreatments on the catalytic properties of the bimetallic Au-Ag catalysts were studied. Catalysts were characterized by low-temperature nitrogen adsorption–desorption, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy. It was found that pretreatments with hydrogen and oxygen at 300 °C significantly decreased the activity of AuAg catalysts (silver was deposited first) and had little effect on the catalytic properties of AgAu samples (gold was deposited first). The density functional theory method demonstrated that the adsorption energy of 1-octanol increased for all positively charged AuxAgyq (x + y = 10, with a charge of q = 0 or +1) clusters compared with the neutral counterparts. Lanthanum oxide was a very effective promoter for both monometallic and bimetallic gold and silver catalysts in the studied process.

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

Nanomaterials ◽

10.3390/nano11061519 ◽

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.

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Study of the Effect of TiO2 Layer on the Adsorption and Photocatalytic Activity of TiO2-MoS2 Heterostructures under Visible-Infrared Light

International Journal of Photoenergy ◽

10.1155/2020/8740825 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

N. Cruz-González ◽

O. Calzadilla ◽

J. Roque ◽

F. Chalé-Lara ◽

J. K. Olarte ◽

...

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Nitrogen Adsorption ◽

High Photocatalytic Activity ◽

Infrared Light ◽

Polluted Water ◽

Light Spectrum ◽

X Ray

In the last decade, the urgent need to environmental protection has promoted the development of new materials with potential applications to remediate air and polluted water. In this work, the effect of the TiO2 thin layer over MoS2 material in photocatalytic activity is reported. We prepared different heterostructures, using a combination of electrospinning, solvothermal, and spin-coating techniques. The properties of the samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS), and X-ray photoelectron spectroscopy (XPS). The adsorption and photocatalytic activity were evaluated by discoloration of rhodamine B solution. The TiO2-MoS2/TiO2 heterostructure presented three optical absorption edges at 1.3 eV, 2.28 eV, and 3.23 eV. The high adsorption capacity of MoS2 was eliminated with the addition of TiO2 thin film. The samples show high photocatalytic activity in the visible-IR light spectrum.

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Evaluation of Hydrocalumite-Like Compounds as Catalyst Precursors in the Photodegradation of 2,4-Dichlorophenoxyacetic Acid

International Journal of Photoenergy ◽

10.1155/2016/5256941 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 3

Author(s):

Manuel Sánchez-Cantú ◽

Clara Barcelos-Santiago ◽

Claudia M. Gomez ◽

Esthela Ramos-Ramírez ◽

Ma. de Lourdes Ruiz Peralta ◽

...

Keyword(s):

Diffuse Reflectance ◽

Diffuse Reflectance Spectroscopy ◽

Nitrogen Adsorption ◽

Dichlorophenoxyacetic Acid ◽

X Ray ◽

2,4 Dichlorophenoxyacetic Acid ◽

Adsorption Desorption ◽

Oxide Ions ◽

Environmentally Friendly Method ◽

Simple Economic

Three hydrocalumite-like compounds in a Ca/Al ratio of 2 containing nitrate and acetate anions in the interlaminar region were prepared by a simple, economic, and environmentally friendly method. The solids were characterized by X-ray powder diffraction (XRD), thermogravimetric (TG) analysis, nitrogen adsorption-desorption at −196°C, scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and UV-Vis Diffuse Reflectance Spectroscopy (DRS). The catalytic activity of the calcined solids at 700°C was tested in the photodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) where 57% degradation of 2,4-D (40 ppm) and a mineralization percentage of 60% were accomplished within 150 minutes. The photocatalytic properties were attributed to mayenite hydration, since the oxide ions in the cages are capable of reacting with water to form hydroxide anions capable of breaking down the 2,4-D molecules.

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

Materials ◽

10.3390/ma12111771 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1771 ◽

Cited By ~ 2

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.

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Synthesis, Characterization, and Photocatalytic Evaluation of Manganese (III) Phthalocyanine Sensitized ZnWO4 (ZnWO4MnPc) for Bisphenol A Degradation under UV Irradiation

Nanomaterials ◽

10.3390/nano10112139 ◽

2020 ◽

Vol 10 (11) ◽

pp. 2139 ◽

Cited By ~ 1

Author(s):

Chukwuka Bethel Anucha ◽

Ilknur Altin ◽

Zekeriya Biyiklioglu ◽

Emin Bacaksiz ◽

Ismail Polat ◽

...

Keyword(s):

Bisphenol A ◽

Uv Irradiation ◽

Photoelectron Spectroscopy ◽

Photocatalytic Performance ◽

Diffuse Reflectance Spectroscopy ◽

Degradation Process ◽

X Ray Diffraction ◽

X Ray ◽

Uv Visible ◽

Adsorption Desorption

ZnWO4MnPc was synthesized via a hydrothermal autoclave method with 1 wt.% manganese (iii) phthalocyanine content. The material was characterized for its structural and morphological features via X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission emission microscopy (TEM), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX), N2 adsorption–desorption at 77K, X-ray photoelectron spectroscopy (XPS), and UV-visible/diffuse reflectance spectroscopy(UV-vis/DRS). ZnWO4MnPc photocatalytic performance was tested on the degradation of bisphenol A (BPA). The ZnWO4MnPc material removed 60% of BPA after 4 h of 365 nm UV irradiation. Degradation process improved significantly to about 80% removal in the presence of added 5 mM H2O2 after 4 h irradiation. Almost 100% removal was achieved after 30 min under 450 nm visible light irradiation in the presence of same concentration of H2O2. The effect of ions and humic acid (HA) towards BPA removal was also investigated.

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VISIBLE LIGHT ACTIVE Cu2+/TiO2 NANOCATALYST FOR DEGRADATION OF DICHLORVOS

International Journal of Nanoscience ◽

10.1142/s0219581x12500305 ◽

2012 ◽

Vol 11 (05) ◽

pp. 1250030 ◽

Cited By ~ 3

Author(s):

TESHOME ABDO SEGNE ◽

SIVA RAO TIRUKKOVALLURI ◽

SUBRAHMANYAM CHALLAPALLI

Keyword(s):

Catalytic Activity ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Light Illumination ◽

X Ray ◽

Photo Catalytic Activity ◽

Visible Light Active ◽

Adsorption Desorption

The advantage of doping of TiO2 with copper has been utilized for enhanced degradation of pesticide under visible light irradiation. The sol–gel method has been undertaken for the synthesis of copper-doped TiO2 by varying the dopant loadings from 0.25 wt.% to 1.0 wt.% of Cu2+ . The doped samples were characterized by UV-Visible Diffuse Reflectance Spectroscopy (DRS), N2 adsorption–desorption (BET), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometry (EDS). The photocatalytic activity of the catalyst was tested by degradation of dichlorvos under visible light illumination. The results found that 0.75 wt.% of Cu2+ doped nanocatalysts have better photo catalytic activity than the rest of percentages doped, undoped TiO2 and Degussa P25. The reduction of band gap was estimated and the influence of the process parameters on photo catalytic activity of the catalyst has been explained.

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

NANO ◽

10.1142/s1793292013500501 ◽

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.

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

10.21203/rs.3.rs-191207/v1 ◽

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.

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

HUE UNIVERSITY JOURNAL OF SCIENCE NATURAL SCIENCE ◽

10.26459/hueuni-jns.v126i1c.4417 ◽

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

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.Keywords: MIL-101, hydrothermal synthesis, metal organic framework-101.

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Synthesis of C-N-S-Tridoped TiO2 from Vietnam Ilmenite Ore and Its Visible Light-Driven-Photocatalytic Activity for Tetracyline Degradation

Journal of Nanomaterials ◽

10.1155/2020/1523164 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Nguyen Thi Lan ◽

Vo Hoang Anh ◽

Hoang Duc An ◽

Nguyen Phi Hung ◽

Dao Ngoc Nhiem ◽

...

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Nitrogen Adsorption ◽

Photocatalytic Decomposition ◽

Raman Scattering Spectroscopy ◽

X Ray ◽

Visible Light Driven

In this study, C-N-S-tridoped TiO2 composite was fabricated from TiO2 prepared from ilmenite ore and thiourea by means of hydrothermal method. The obtained material was characterized by X-ray diffraction, Raman scattering spectroscopy, UV-Vis diffuse reflectance spectroscopy, nitrogen adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that C-N-S-tridoped TiO2 material has a large specific surface area, showing good photocatalytic activity on the degradation of antibiotic tetracycline in visible light region. The study on the mechanism of tetracycline photodegradation using the liquid chromatography with mass spectrometry was performed. It was found that tetracycline has been degraded over C-N-S-tridoped TiO2 catalyst into many different intermediates which can eventually be converted into CO2 and H2O. The kinetics of photocatalytic decomposition of tetracycline were investigated. In addition, the obtained material could catalyze well the degradation of other antibiotics (ciprofloxacin and chloramphenicol) and dyes (rhodamine-B, methylene blue, and organe red). The catalyst was stable after five recycles with slight loss of catalytic activity, which indicates great potential for practical application of C-N-S-tridoped TiO2 catalyst in treatment of wastewater containing tetracycline in particular or antibiotics in general.

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