scholarly journals The Preparation and Catalytic Properties of Nanoporous Pt/CeO2 Composites with Nanorod Framework Structures

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 683 ◽  
Author(s):  
Haiyang Wang ◽  
Dong Duan ◽  
Chen Ma ◽  
Wenyu Shi ◽  
Miaomiao Liang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Structural Parameters ◽  
Active Oxygen Species ◽  
Pt Nanoparticles ◽  
Strong Interactions ◽  
X Ray ◽  
Small Pore ◽  
Melt Spun

Pt/CeO2 catalysts with nanoporous structures were prepared by the facile dealloying of melt-spun Al92−XCe8PtX (X = 0.1; 0.3 and 0.5) ribbons followed by calcination. The phase compositions and structural parameters of the catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The specific surface area and pore size distribution were characterized by N2 adsorption–desorption tests. The catalytic properties were evaluated by a three-way catalyst (TWC) measurement system. The results revealed that the dealloyed samples exhibited a nanorod framework structure. The Pt nanoparticles that formed in situ were supported and highly dispersed on the CeO2 nanorod surface and had sizes in the range of 2–5 nm. For the catalyst prepared from the melt-spun Al91.7Ce8Pt0.3 ribbons, the 50% CO conversion temperature (T50) was 91 °C, and total CO could be converted when the temperature was increased to 113 °C. An X-ray photoelectron spectroscopy (XPS) test showed that the Pt0.3/CeO2 sample had a slightly richer oxygen vacancy; and a H2 temperature-programmed reduction (H2-TPR) test demonstrated its superior adsorption ability for reduction gas and high content of active oxygen species. The experiments indicated that the catalytic performance could be retained without any attenuation after 130 h when water and CO2 were present in the reaction gas. The favorable catalytic activities were attributed to the high specific areas and small pore and Pt particle sizes as well as the strong interactions between the CeO2 and Pt nanoparticles. The Pt nanoparticles were embedded in the surface of the CeO2 nanorods, inhibiting growth. Therefore, the catalytic stability and water resistance were excellent.

scholarly journals Heterogeneous Fenton-like oxidation of p-hydroxybenzoic acid using Fe/CeO2-TiO2 catalyst

2019 ◽  
Vol 79 (7) ◽  
pp. 1276-1286 ◽  
Author(s):  
Tijani Hammedi ◽  
Mohamed Triki ◽  
Mayra G. Alvarez ◽  
Jordi Llorca ◽  
Abdelhamid Ghorbel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Molar Ratio ◽  
Hydroxybenzoic Acid ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Temperature Programmed

Abstract This paper is built on the Fenton-like oxidation of p-hydroxybenzoic acid (p–HBZ) in the presence of H2O2 and 3%Fe supported on CeO2-TiO2 aerogels under mild conditions. These catalysts were deeply characterized by X-ray diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The effect of thermal treatment, pH (2–3, 5, 7), H2O2/p–HBZ molar ratio (5, 15, 20, 25) and reaction temperature (25 °C, 40 °C and 60 °C) on the catalytic properties of supported Fe catalysts are studied. Our results highlight the role of CeO2 and the calcination of the catalyst to obtain the highest catalytic properties after 10 min: 73% of p–HBZ conversion and 52% of total organic carbon (TOC) abatement.

Electroless Synthesis of 1.4 nm Pd and Pt Nanoparticles on Self-Assembled Rosette Nanotubes

2011 ◽  
Vol 1301 ◽  
Author(s):  
Rahul Chhabra ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Pt Nanoparticles ◽  
Hierarchical Organization ◽  
X Ray ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Atomic Force ◽  
Transmission Electron ◽  
Self Assembled

ABSTRACTElectroless synthesis and hierarchical organization of 1.4 nm Pd and Pt nanoparticles (NPs) on self-assembled Rosette Nanotubes (RNTs) is described. The nucleated NPs are nearly monodisperse and reveal supramolecular organizations guided by RNT templates. Interestingly, the narrow size distribution is attributable to unique templating behavior of RNTs. The resulting metal NP-RNT composites were characterized by Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). X-ray Photoelectron Spectroscopy (XPS) was also performed to confirm the nature and composition of RNT-templated NPs.

TEMPLATE STRATEGY FOR THE SYNTHESIS OF Cu2O–Pt HIERARCHICAL HETEROSTRUCTURES FOR THE DEGRADATION OF METHYLENE BLUE

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350062 ◽  
Author(s):  
SHIYONG BAO ◽  
HAN ZHU ◽  
PAN WANG ◽  
MEILING ZOU ◽  
MINGLIANG DU ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Transmission Electron ◽  
Green Route

A facile and green route was introduced to synthesize Pt nanoparticles (PtNPs) immobilized on Cu 2 O octahedrons to form Cu 2 O – Pt hierarchical heterostructure. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were employed to study their morphology, chemical and crystallographic properties of the Cu 2 O – Pt hierarchical heterostructure. These novel Cu 2 O – Pt hierarchical heterostructures show fascinating degradations of methylene blue (MB), due to the suppressed electron/hole recombination phenomena and the efficient ability to capture the light.

Chemical Deposition Method for Synthesis of Pt-TiO2 Composite Nanotubes with Photoelectrochemical Activity

2012 ◽  
Vol 465 ◽  
pp. 276-282
Author(s):  
Zhong Hui Gao ◽  
Zhen Duo Cui ◽  
Xian Jin Yang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Chemical Deposition ◽  
Pt Nanoparticles ◽  
High Density ◽  
Deposition Method ◽  
Photoelectrochemical Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Chemical Deposition Method

Pt nanoparticles were successfully assembled in self-organized TiO2 nanotubes by a chemical deposition method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used for characterizing the surface morphology and phase composition. Photocurrent response activity was measured. Different morphology of Pt-TiO2 NTs exhibited different photocurrent generation efficiency. High density Pt nanoparticles depositing on TiO2 NTs decreased the photocurrent of Pt-TiO2 electrodes. It was because the high density Pt nanoparticles could become the recombination centers of photoelectrons and holes.

scholarly journals A Colorimetric Assay for the Detection of Glucose and H2O2 Based on Cu-Ag/g-C3N4/ZIF Hybrids with Superior Peroxidase Mimetic Activity

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4432
Author(s):  
Quan Pan ◽  
Yuelin Kong ◽  
Kuan Chen ◽  
Mi Mao ◽  
Xiaohui Wan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Colorimetric Assay ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Transmission Electron ◽  
H2o2 Generation

In this work, we report the synthesis of Cu-Ag bimetallic nanopartiles and g-C3N4 nanosheets decorated on zeolitic imidazolate framework-8 (ZIF-8) to form a Cu-Ag/g-C3N4/ZIF hybrid. The hybrid was synthesized and characterized by Transmission electron microscopy (TEM), Fourier transformed infrared (FTIR), the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Cu-Ag/g-C3N4/ZIF hybrid has intrinsic peroxidaselike catalytic activity towards the oxidation of TMB in the presence of H2O2. The situ synthesis of Cu-Ag bimetallic nanopartiles on 2D support such as g-C3N4 nanosheets would significantly enhance the peroxidaselike catalytic properties of individual Cu-Ag bimetallic nanopartiles and the g-C3N4 nanosheets. After loading of Cu-Ag bimetallic nanopartiles and g-C3N4 nanosheets on the ZIF-8, the hybrids exhibited superior peroxidaselike catalytic activity and good recyclability. Then, this method was applied for detecting glucose in human serum, owing the significant potential for detection of metabolites with H2O2-generation reactions.

scholarly journals Propylsulfonic Acid Functionalized SBA-15 Mesoporous Silica as Efficient Catalysts for the Acetalization of Glycerol

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 297 ◽  
Author(s):  
Ruiyun Li ◽  
Heyuan Song ◽  
Jing Chen
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Structural Parameters ◽  
Catalytic Performance ◽  
Cyclic Acetals ◽  
X Ray ◽  
Composition And Structure ◽  
Optimum Reaction ◽  
Adsorption Desorption ◽  
And Control

As the main by-product obtained from biomass, glycerol could be converted into valuable chemicals. Tunable propylsulfonic acid functionalized SBA-15 and KIT-6 with different structural parameters have been prepared by different methods while using 3-mercaptopropyltrimethoxysilane (MPTMS) as the source of sulfur. The composition and structure of the synthesized catalysts have been well-characterized by N2 adsorption-desorption (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalytic performance of the prepared catalysts have been evaluated and compared in glycerol acetalization with formaldehyde to the mixture of 1,3-dioxane-5-ol and 1,3-dioxolane-4-methanol. Optimum reaction parameters were investigated to enhance the yield of products and control the distribution of glycerol formals. More than 90% yield of cyclic acetals were obtained with the ratio of two isomers 5R to 6R of 42:58.

Pt Nanoparticles Decorated on Fe2O3/N, P-Doped Mesoporous Carbon for Enhanced Oxygen Reduction Activity and Durability

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Sabarinathan Ravichandran ◽  
Narayanamoorthy Bhuvanendran ◽  
Kai Peng ◽  
Weiqi Zhang ◽  
Qian Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Chemical Reduction ◽  
Pt Nanoparticles ◽  
Active Surface ◽  
Alkaline Media ◽  
Active Surface Area ◽  
X Ray

Abstract The Pt–Fe2O3 nanoparticles embedded over N, P-doped carbon (Pt–Fe2O3/NPC) was successfully synthesized by chemical reduction method demonstrating an enhanced electrocatalytic efficacy in alkaline media toward oxygen reduction reaction (ORR). The surface morphology of Pt–Fe2O3/NPC has been characterized by electron microscopy scanning, X-ray diffraction, electron microscopy transmission, Raman spectra, and X-ray photoelectron spectroscopy. The ORR electrocatalytic activity of Pt–Fe2O3/NPC was found to be the superior mass activity of 0.120 mA µg−1, which are almost twice higher than those for Pt–Fe2O3/VC (0.068 mA µg−1) and Pt/C (0.061 mA µg−1) catalysts. The durability tests revealed that the Pt–Fe2O3/NPC exhibited enhanced stability observed from the order of electrochemical active surface area (ECA) loss determined as Pt–Fe2O3/NPC (45.67%) <Pt–Fe2O3/VC (62.5%) <(Pt/C (72.13%) after 5000 cycles. This present investigation unveiled a facile approach to develop the number of active sites with the combination between P–Fe2O3 and N, P-doped carbon for improved electrocatalytic performance toward ORR.

Antibacterial silver-diatomite nanocomposite ceramic with low silver release

2019 ◽  
Vol 20 (2) ◽  
pp. 633-643
Author(s):  
Xiaopeng Qi ◽  
Junwei Chen ◽  
Qian Li ◽  
Hui Yang ◽  
Honghui Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Water Treatment ◽  
Photoelectron Spectroscopy ◽  
Bactericidal Effect ◽  
Ceramic Filter ◽  
Ceramic Filters ◽  
X Ray ◽  
E Coli ◽  
Point Of Use ◽  
Silver Release

Abstract There is an urgent need for an effective and long-lasting ceramic filter for point-of-use water treatment. In this study, silver-diatomite nanocomposite ceramic filters were developed by an easy and effective method. The ceramic filters have a three-dimensional interconnected pore structure and porosity of 50.85%. Characterizations of the silver-diatomite nanocomposite ceramic filters were performed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Silver nanoparticles were confirmed to be formed in situ in the ceramic filter. The highest silver concentration in water was 0.24 μg/L and 2.1 μg/L in short- and long-term experiments, indicating very low silver-release properties of silver-diatomite nanocomposite ceramic filter. The nanocomposite ceramics show strong bactericidal activity. When contact time with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of 105 colony forming units (CFU)/mL exceeded 3 h, the bactericidal rates of the four different silver content ceramics against E. coli and S. aureus were all 100%. Strong bactericidal effect against E. coli with initial concentration of 109 CFU/mL were also observed in ceramic newly obtained and ceramic immersed in water for 270 days, demonstrating its high stability. The silver-diatomite nanocomposite ceramic filters could be a promising candidate for point-of-use water treatment.

scholarly journals Phytosynthetic Fabrication of Lanthanum Ion-Doped Nickel Oxide Nanoparticles Using Sesbania grandiflora Leaf Extract and Their Anti-Microbial Properties

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 124
Author(s):  
Srihasam Saiganesh ◽  
Thyagarajan Krishnan ◽  
Golla Narasimha ◽  
Hesham S. Almoallim ◽  
Sulaiman Ali Alhari ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Rare Earth ◽  
Nickel Oxide ◽  
Photoelectron Spectroscopy ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Nio Nanoparticles ◽  
X Ray ◽  
Sesbania Grandiflora

Over the past few years, the photogenic fabrication of metal oxide nanoparticles has attracted considerable attention, owing to the simple, eco-friendly, and non-toxic procedure. Herein, we fabricated NiO nanoparticles and altered their optical properties by doping with a rare earth element (lanthanum) using Sesbania grandiflora broth for antibacterial applications. The doping of lanthanum with NiO was systematically studied. The optical properties of the prepared nanomaterials were investigated through UV-Vis diffuse reflectance spectra (UV-DRS) analysis, and their structures were studied using X-ray diffraction analysis. The morphological features of the prepared nanomaterials were examined by scanning electron microscopy and transmission electron microscopy, their elemental structure was analyzed by energy-dispersive X-ray spectral analysis, and their oxidation states were analyzed by X-ray photoelectron spectroscopy. Furthermore, the antibacterial action of NiO and La-doped NiO nanoparticles was studied by the zone of inhibition method for Gram-negative and Gram-positive bacterial strains such as Escherichia coli and Bacillus sublitis. It was evident from the obtained results that the optimized compound NiOLa-04 performed better than the other prepared compounds. To the best of our knowledge, this is the first report on the phytosynthetic fabrication of rare-earth ion Lanthanum (La3+)-doped Nickel Oxide (NiO) nanoparticles and their anti-microbial studies.

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