Surface and bulk characterization of Rh/ZrO2 prepared by absorption of Rh4(CO)12 clusters on ZrO2 powder

1997 ◽  
Vol 12 (5) ◽  
pp. 1376-1384 ◽  
Author(s):  
L. E. Depero ◽  
R. Bertoncello ◽  
T. Boni ◽  
P. Levrangi ◽  
I. Natali Sora ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Profile Analysis ◽  
Spectral Component ◽  
Metallic Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Surface And Bulk Characterization ◽  
Core Line ◽  
Average Size ◽  
Auger Microscopy

Rh nanoparticles supported on ZrO2 powder were prepared by adsorbing Rh4(CO)12 clusters from hexane solution under Ar atmosphere. Four samples with Rh content ranging from 0.25 Rh wt.% up to 4.10 Rh wt.% were studied by x-ray diffraction (XRD), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), scanning Auger microscopy (SAM), and time of flight secondary ion mass spectroscopy (ToF-SIMS). TEM measurements show, for all the samples, Rh particles with a size of about 50 Å. The 4.10 Rh wt.% sample also shows some agglomerates of Rh nanoparticles and only for this sample Rh metallic phase was detected by XRD. The profile analysis of the XRD lines indicates an average size of the Rh crystallites of about 60 Å. XPS studies show only a single spectral component for the Zr3d5/2 core line at 182.2 eV. Instead, at least, two components at 307.2 eV and 308.5 eV are detected for the Rh3d5/2 core line. These results suggest that Zr is present only as oxidized state, whereas nonoxidized and oxidized Rh are both observed. A nonoxidized Rh state is also suggested by the XPS valence band electron removal spectrum which exhibits a significant emission within the ZrO2 band gap assigned to Rh 4d bands. A further support to this finding arises from scanning Auger maps of OKVV and RH where nonoxidized Rh is observed. Finally scanning Auger maps using the OKVV and the Zr emissions show surface regions where only the Zr Auger lines are detected, whereas on pure ZrO2 powder this effect is not observed. Since it is possible to rule out from the XPS Zr3d core line spectra, the presence of metallic zirconium hydrogen spillover mechanisms is invoked to explain this result.

Preparation and Characterization of CdSe Nanoparticles Synthesized Using the Ultrasonic Irradiation

2007 ◽  
Vol 124-126 ◽  
pp. 1229-1232 ◽  
Author(s):  
Myoung Seok Sung ◽  
Yoon Bok Lee ◽  
Yong Jin Kim ◽  
Yang Do Kim
Keyword(s):  
Ultrasonic Irradiation ◽  
Photoelectron Spectroscopy ◽  
Irradiation Time ◽  
Xrd Analysis ◽  
Cdse Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Emission ◽  
Transmission Electron ◽  
Average Size

Cadmium selenide(CdSe) nanoparticles were prepared in the aqueous solution containing isopropyl alcohol by the ultrasonic irradiation at room temperature. The cadmium chloride (CdCl2) and sodium selenosulfate (Na2SeSO3) were used as the cadmium and selenium source, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-Vis absorption spectra and PL spectra were used to characterize the CdSe nanoparticles. XRD analysis revealed the formation of cubic structure CdSe. TEM images showed aggregated CdSe nanoparticles with the size of nanometer scale. Average size of CdSe nanoparticles were about 3.9, 5.0 and 5.1nm with sonication time of 6, 30 and 40 minutes, respectively. The surface emission became less intensive and shifted to red with increasing irradiation time. This paper presents the effects of ultrasonic on the formation of CdSe nanoparticles and its characteristics.

A COST-EFFECTIVE MAGNETIC PHOTOCATALYST PALYGORSKITE–TiO2–FexOy WITH EXCELLENT PERFORMANCE FOR DYE PHOTODEGRADATION UNDER VISIBLE LIGHT

NANO ◽  
2014 ◽  
Vol 09 (06) ◽  
pp. 1450063
Author(s):  
JIAHUI ZHANG ◽  
LILI ZHANG ◽  
JIN HUANG ◽  
SHOUYONG ZHOU ◽  
HAIQUN CHEN ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Cost Effective ◽  
Magnetic Photocatalyst ◽  
X Ray ◽  
Transmission Electron ◽  
Light Region ◽  
Reaction Solution ◽  
Excellent Photocatalytic Activity ◽  
Average Size

Palygorskite (denoted as Pal) was used as an economical carrier of hybrid photocatalyst TiO 2– Fe x O yvia an in situ depositing technique (marked as Pal– TiO 2– Fe x O y). The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), brunner-emmet-teller (BET) measurements, X-ray photoelectron spectroscopy (XPS) and UV-Vis diffuse reflectance spectra measurements. Results showed that TiO 2– Fe x O y composite particles with average size of about 10 nm were loaded onto the Pal fibers' surface. Fe x O y acted not only as magnetic source but also took part in the formation of TiO 2– Fe x O y heterojunction structure, which resulted in the obvious absorption in visible light region for the obtained Pal– TiO 2– Fe x O y composite photocatalyst. The obtained Pal– TiO 2– Fe x O y shows excellent photocatalytic activity toward photodegradation of Methyl orange (MO) under visible light irradiation and the degradation ratio reached 94% within 180 min. Moreover, Pal– TiO 2– Fe x O y could be readily recovered from the reaction solution by the magnet. Possible mechanism for the enhancement was also proposed.

A facile wet chemical route to prepare ZnO/TiO2 nanotube composites and their photocatalytic activities

2010 ◽  
Vol 25 (7) ◽  
pp. 1278-1287 ◽  
Author(s):  
Lei Zhu ◽  
Guocong Liu ◽  
Xuechen Duan ◽  
Zhi Jian Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Zno Nps ◽  
Wurtzite Phase ◽  
Chemical Route ◽  
X Ray ◽  
Transmission Electron ◽  
Nanotube Composites ◽  
Electron Hole Pair ◽  
Average Size

Highly dispersed ZnO/TiO2 nanotube composites (NTCs) were successfully synthesized by a facile ethylenediamine-assisted deposition-precipitation route. The characterizations from x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller, Fourier transform infrared, and ultraviolet-visible spectra revealed that hexagonal wurtzite phase ZnO NPs with an average size of about 2 nm were homogeneously dispersed and anchored on the surface of TiO2 nanotubes (NTs) to form ZnO/TiO2 NTCs. The as-prepared ZnO/TiO2 NTCs with the atom ratio Zn/Ti of 1:4 exhibited excellent photocatalytic activity for photodegradation of methyl orange compared with P25 and pure TiO2 NTs, which were mainly caused by an increase of interfacial charge transfer reactions and a decrease of electron-hole pair recombination on ZnO-TNTs heterojunction. Furthermore, ZnO/TiO2 NTCs possessed favorable recycle efficiency due to their relatively high sedimentation rate and only a slight decrease of photocatalytic activity after a six time recycle.

scholarly journals Activity and Stability of Trypsin Immobilized onto Chitosan Magnetic Nanoparticles

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Jun Sun ◽  
Bin Xu ◽  
Yu Shi ◽  
Lin Yang ◽  
Hai-le Ma
Keyword(s):  
Magnetic Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Covalent Immobilization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Immobilized Trypsin ◽  
Alkaline Conditions ◽  
Ph Range ◽  
Average Size

The aim of this study was to develop a thermally and operationally stable trypsin through covalent immobilization onto chitosan magnetic nanoparticles (Fe3O4 @CTS). The successful preparation of the Fe3O4 @CTS nanoparticles was verified by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM), which indicated that the prepared Fe3O4 @CTS nanoparticles have superparamagnetic properties, with an average size of approximately 17 nm. Then, trypsin was covalently immobilized onto the Fe3O4 @CTS nanoparticles at a high loading capacity (149.25 mg/g). The FTIR data demonstrated that the trypsin had undergone a conformational change compared with free trypsin, and the Michaelis constant (Km) and the maximum hydrolysis reaction rate (Vmax) showed that the trypsin immobilized on the Fe3O4 @CTS had a lower affinity for BAEE and lower activity compared with free trypsin. However, the immobilized trypsin showed higher activity than free trypsin at pH 6.0 and in alkaline conditions and retained more than 84% of its initial activity at 60°C after 8 h incubation. Its excellent performance across a broader pH range and high thermal stability, as well as its effective hydrolysis of bovine serum albumin (BSA) and its reusability, make it more attractive than free trypsin for application in protein digestion.

scholarly journals Synthesis of gold nanoparticles using Platycodon grandiflorum extract and its antipathogenic activity under optimal conditions

2020 ◽  
Vol 10 ◽  
pp. 184798042096169
Author(s):  
Periasamy Anbu ◽  
Subash CB Gopinath ◽  
S Jayanthi
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Plant Extracts ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Platycodon Grandiflorum ◽  
Transmission Electron ◽  
Flower Plant ◽  
Average Size

Gold nanoparticles have many applications in the biomedical field, mainly for drug delivery, cancer therapy, and detection of pathogenic microorganisms. In this study, gold nanoparticles synthesized using Platycodon grandiflorum (Balloon flower plant) extracts were evaluated for their antibacterial potential. Gold nanoparticles were synthesized at 20–50°C using different volumes of the leaf extract. Biosynthesis of gold nanoparticles was confirmed by ultraviolet–visible spectral absorption at 545 nm by surface plasmon resonance. The morphology and size of the P. grandiflorum gold nanoparticles were further characterized as spherical in shape with an average size of 15 nm in diameter by scanning electron microscopy and transmission electron microscopy. Energy-dispersive X-ray analysis clearly displayed the presence of gold particles. The structural analysis results with face central cubic crystalline nature and elemental composition, including gold, were confirmed by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. In addition, Fourier transform infrared results identified the functional group in P. grandiflorum that is involved in the reduction of metal ions to gold nanoparticles. The synthesized P. grandiflorum gold nanoparticles exhibited efficient antibacterial activity against Escherichia coli (16 mm) and Bacillus subtilis (11 mm). This report confirms the synthesis of gold nanoparticle from balloon flower plant extracts, which can be used as a reducing and stabilizing agent and demonstrates its antibacterial applications.

scholarly journals Synthesis and Characterization of Antibacterial Viscose Nonwoven Fabric by the Cooperative Action of Se Nanoparticles and Amino Hyperbranched Polymer

2021 ◽  
Author(s):  
Yao Xiao ◽  
Zhenzheng Gan ◽  
Erying Dong ◽  
Jiawei Yan ◽  
Wanwan Liu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fiber Surface ◽  
Nonwoven Fabric ◽  
Impregnation Method ◽  
Bacterial Reduction ◽  
X Ray ◽  
Cooperative Action ◽  
Transmission Electron ◽  
Cellulose Fabrics ◽  
Average Size

Abstract This research provides a new method for preparing nanoparticle-coated cellulose fabrics, which has broad application prospects in the functional fiber industry. In this work amino-terminated hyperbranched poly (HBP)-capped Selenium nanoparticles (Se NPs) were synthesized for coating viscose nonwoven fabric (VNF) via impregnation method to produce a controllable and uniform Se NPs coating on the viscose fiber surface. The prepared Se NPs and the treated VNF were characterized by the transmission electron microscope (TEM), x-ray diraction (XRD), x-ray photoelectron spectroscopy (XPS), field emission scanning electron microcopy (FE-SEM), and antibacterial measurement. The results indicate that the Se NPs were spherical shaped with an average size of 10 nm. FESEM, XRD, and XPS characterizations demonstrated that Se NPs can adsorbed and distributed uniformly on the fiber surface. Se NPs-coated VNF showed above 99.9% bacterial reduction of Staphylococcus aureus and Escherichia coli while the Se element content on VNF was about 292 mg/kg.

scholarly journals A study of electrocatalytic ethanol oxidation of nanoporous PtSi alloy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nali Lu ◽  
Yao Li ◽  
Lei Zhang ◽  
Yong Fang ◽  
Bin Qian ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
Oxidation Reactions ◽  
X Ray Diffraction ◽  
Direct Ethanol Fuel Cells ◽  
X Ray ◽  
Transmission Electron ◽  
Bicontinuous Structure ◽  
Average Size ◽  
Catalyzed Oxidation

In recent years, nanoporous alloys have presented the advantages of a large specific surface area, low density, and simple operation, and they have been widely used in the fields of catalysis, magnetism, and medicine. Nanoporous Pt-Si alloy was prepared by melt-spun and chemical dealloying, and was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscopy. Pt-Si alloys possess a three-dimensional bicontinuous structure and an average size of 5 nanometers. Compared with commercial Pt/C catalysts, nanoporous Pt-Si alloys exhibit excellent electrocatalytic activity and stability in ethanol-catalyzed oxidation reactions. It is taken into consideration to be a promising catalyst in direct ethanol fuel cells.

scholarly journals α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 581
Author(s):  
Gajanan S. Ghodake ◽  
Surendra K. Shinde ◽  
Ganesh D. Saratale ◽  
Rijuta G. Saratale ◽  
Min Kim ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Photoelectron Spectroscopy ◽  
Cellulose Fibers ◽  
Relative Activity ◽  
Significant Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Laccase Immobilization ◽  
Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

scholarly journals Novel Carbon Dots Derived from Glycyrrhizae Radix et Rhizoma and Their Anti-Gastric Ulcer Effect

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1512
Author(s):  
Yuhan Liu ◽  
Meiling Zhang ◽  
Jinjun Cheng ◽  
Yue Zhang ◽  
Hui Kong ◽  
...  
Keyword(s):  
Gastric Ulcer ◽  
Photoelectron Spectroscopy ◽  
Carbon Dots ◽  
High Performance ◽  
Raw264.7 Cells ◽  
Mice Model ◽  
X Ray ◽  
Glycyrrhizae Radix ◽  
Transmission Electron ◽  
High Resolution Tem

Glycyrrhizae Radix et Rhizoma (GRR) is one of the commonly used traditional Chinese medicines in clinical practice, which has been applied to treat digestive system diseases for hundreds of years. GRR is preferred for anti-gastric ulcer, however, the main active compounds are still unknown. In this study, GRR was used as precursor to synthesize carbon dots (CDs) by a environment-friendly one-step pyrolysis process. GRR-CDs were characterized by using transmission electron microscopy, high-resolution TEM, fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. In addition, cellular toxicity of GRR-CDs was studied by using CCK-8 in RAW264.7 cells, and the anti-gastric ulcer activity was evaluated and confirmed using mice model of acute alcoholic gastric ulcer. The experiment confirmed that GRR-CDs were the spherical structure with a large number of active groups on the surface and their particle size ranged from 2 to 10 nm. GRR-CDs had no toxicity to RAW264.7 cells at concentration of 19.5 to 5000 μg/mL and could reduce the oxidative damage of gastric mucosa and tissues caused by alcohol, as demonstrated by restoring expression of malondialdehyde, superoxide dismutase and nitric oxide in serum and tissue of mice. The results indicated the explicit anti-ulcer activity of GRR-CDs, which provided a new insights for the research on effective material basis of GRR.

Highly active carbon nanotube–promoted Rh-Mn-Li/SiO2 catalysts for the synthesis of C2+ oxygenates from syngas

2021 ◽  
pp. 174751982098472
Author(s):  
Jun Yu ◽  
Ying Han ◽  
Guoqing Chen ◽  
Xiuzhen Xiao ◽  
Haifang Mao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Co Hydrogenation ◽  
X Ray ◽  
Highly Active ◽  
Transmission Electron ◽  
Co Insertion ◽  
Temperature Programmed Surface Reaction ◽  
Temperature Programmed ◽  
Oxygenate Synthesis

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis.

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