Atomic Structure of PtRu Nanoparticle Catalysts and Their Methanol Oxidation Activity

2007 ◽  
Vol 1056 ◽  
Author(s):  
Hiroaki Nitani ◽  
Yusuke Honda ◽  
Ryo Horioka ◽  
Kosuke Ohara ◽  
Takuya Kawaguchi ◽  
...  
Keyword(s):  
Atomic Structure ◽  
Gamma Ray ◽  
Bimetallic Nanoparticles ◽  
Clear Correlation ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
X Ray ◽  
Nanoparticle Catalysts ◽  
Transmission Electron ◽  
Gamma Ray Irradiation

ABSTRACTPtRu bimetallic nanoparticles supported on carbon nanoparticle (PtRu/C) catalysts were synthesized with radiation irradiation. The samples were structural analyzed by techniques of X-ray absorption fine structure (XAFS), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results indicated that PtRu/C catalysts which prepared by an electron beam irradiation had more homogeneous atomic arrangement than that prepared by a gamma-ray irradiation. We found a clear correlation between the atomic structure and the catalytic activity of PtRu/C catalysts. These results supported the bi-functional mechanism.

Instrumentation for X-Ray Diffraction Studies of Highly Radioactive Samples

1958 ◽  
Vol 2 ◽  
pp. 107-115
Author(s):  
Vincent G. Scotti ◽  
James I. Mueller ◽  
John J. Little
Keyword(s):  
Radiation Damage ◽  
Gamma Ray ◽  
Pulse Height ◽  
Fission Products ◽  
Analytical Tool ◽  
Nuclear Engineering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Background Ratio ◽  
Gamma Ray Irradiation

AbstractWith the advent of nuclear engineering, x-ray diffraction has become an important analytical tool in the study of radiation damage due to neutron and gamma-ray irradiation. The materials under study in this work have rdioactive levels up to 40 R/hr. at 17 centimeters combined β and γ. The activity of the various samples under study may be due to (n, γ) reactions or fission products or both.Data are presented to illustrate the use of sample shielding, detector shielding pulse height discrimination and the combination of all three aids in an effort to attain the most favorable peak to background ratio.

scholarly journals Thermal CO Oxidation and Photocatalytic CO2 Reduction over Bare and M-Al2O3 (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) Cotton-Like Nanosheets

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1278
Author(s):  
Heejung Yoon ◽  
Juhyun Yang ◽  
Sojeong Park ◽  
Youngku Sohn
Keyword(s):  
Electron Microscopy ◽  
Transition Metals ◽  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Co2 Reduction ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
X Ray ◽  
Transmission Electron

Aluminum oxide (Al2O3) has abundantly been used as a catalyst, and its catalytic activity has been tailored by loading transition metals. Herein, γ-Al2O3 nanosheets were prepared by the solvothermal method, and transition metals (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) were loaded onto the nanosheets. Big data sets of thermal CO oxidation and photocatalytic CO2 reduction activities were fully examined for the transition metal-loaded Al2O3 nanosheets. Their physicochemical properties were examined by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. It was found that Rh, Pd, Ir, and Pt-loading showed a great enhancement in CO oxidation activity while other metals negated the activity of bare Al2O3 nanosheets. Rh-Al2O3 showed the lowest CO oxidation onset temperature of 172 °C, 201 °C lower than that of bare γ-Al2O3. CO2 reduction experiments were also performed to show that CO, CH3OH, and CH4 were common products. Ag-Al2O3 nanosheets showed the highest performances with yields of 237.3 ppm for CO, 36.3 ppm for CH3OH, and 30.9 ppm for CH4, 2.2×, 1.2×, and 1.6× enhancements, respectively, compared with those for bare Al2O3. Hydrogen production was found to be maximized to 20.7 ppm during CO2 reduction for Rh-loaded Al2O3. The present unique pre-screening test results provided very useful information for the selection of transition metals on Al2O3-based energy and environmental catalysts.

scholarly journals Synthesis of Chromium Carbide Nanopowders by Microwave Heating and Their Composition and Microstructure Change under Gamma Ray Irradiation

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 16 ◽  
Author(s):  
Kai Jin ◽  
Yuanbo Jia ◽  
Zhiwei Zhao ◽  
Weiqiang Song ◽  
Shun Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microwave Heating ◽  
Chromium Carbide ◽  
Photoelectron Spectroscopy ◽  
Gamma Ray ◽  
X Ray ◽  
Transmission Electron ◽  
Before And After ◽  
Gamma Ray Irradiation

Chromium carbide nanopowders were synthesized by mechanical alloying-assisted microwave heating. The effect of gamma irradiation on phase composition and microstructure of chromium carbide nanopowders synthesized by the microwave heating method was analyzed. The samples were characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The results showed that well-dispersed chromium carbide nanopowders can be synthesized by maintaining the temperature at 1000 °C for 1 h. Gamma ray irradiation had an important effect on the microstructure of chromium carbide nanopowders. The interplanar spacings of chromium carbide (110) crystal faces before and after gamma ray irradiation were 0.3725 nm and 0.3824 nm, respectively. The crystal structure of chromium carbide was changed by gamma ray irradiation. Gamma ray irradiation can also increase the binding energy of chromium carbide, which is beneficial to improve the thermal stability and mechanical properties of chromium carbide at high temperature.

scholarly journals Defect Persuade Paramagnetic Properties of Nickel Doped ZnS Nanocrystals and Identification of Structural, Optical, Local Atomic Structure

2021 ◽  
Author(s):  
Soumendra Ghorai ◽  
Dibyendu Bhattacharyya ◽  
Nirmalendu Patra ◽  
Shambhu Nath Jha ◽  
Anup K Ghosh
Keyword(s):  
Electron Microscopy ◽  
Atomic Structure ◽  
Defect Formation ◽  
Local Atomic Structure ◽  
X Ray Diffraction ◽  
Edge Structure ◽  
X Ray ◽  
Local Structures ◽  
Transmission Electron ◽  
X Ray Absorption

Abstract We have methodically investigated the structural, spectroscopic, local atomic structure and magnetic properties of aquatic Zn1-xNixS (0≤x≤0.04) nanocrystals. The structural study of synthesized samples are observed by X-ray diffraction datas with Rietveld refinement. Proficient decrease of lattice parameters and inter-planar spacing are determined on Zn1-xNixS nanocrystals. The nanocrystalline microstructure is identified by high resolution transmission electron microscopy. The sphalerite morphology of doped samples are observed by scanning electron microscopy. Shrinkage of energy band gap is observed for doped nanocrystals. Defect formation due to doping of Ni ion is observed by photoluminescence spectroscopy with cyan color emission. X-ray absorption spectroscopy is employed for identification of local structures surrounding of Zn and Ni sites of Zn1-xNixS nanocrystals. Extended X-ray absorption fine structure investigation evidenced the existence of nanocluster within the lattice of Zn1-xNixS nanocrystals. X-ray absorption near edge structure studies confirmed incorporation of Ni2+ in ZnS lattice of Zn1-xNixS nanocrystals. The single pre-edge feature at Ni K-edge is not relying on concentration of Ni dopant in Zn1-xNixS nanocrystals. The presence of interstitial Ni is identified by significant fraction of Ni-Ni scattering paths on doped samples. Zn1-xNixS nanocrystals exhibit defect persuaded paramagnetism at room temperature.

Preparation of Gold Nanoparticles Supported on Montmorillonite and its Catalytic Activity for CO Oxidation

2014 ◽  
Vol 955-959 ◽  
pp. 51-55
Author(s):  
Ting Ting Hu ◽  
Lin Hua Zhu
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Oxidation Reaction ◽  
Fluorescence Analysis ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Gold Precursor

Gold catalysts supported on Na-MMT and Al-PILM noted as Au/Na-MMT and Au/Al-PILM respectively were prepared using Au(en)2Cl3 as precursor, and the catalytic oxidation activity for CO oxidation was investigated. The influence of different carriers on the conversion of CO was discussed. The phase of catalysts, the actual gold loading and the morphology of gold nanoparticles were characterized by X-ray diffraction(XRD), X-ray fluorescence analysis(XRF) and Transmission electron microscopy(TEM). The results showed that Au/Al-PILM exhibited higher catalytic activity for the oxidation reaction of CO, and 100% conversion of CO was achieved at reaction temperature of 250°C when gold precursor was loaded on the Al-PILM carrier at 60°Cand calcined it at 450°C for 1h.

scholarly journals Effects of Gamma-Ray Irradiation on Hardened Cement Mortar

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Yuliia Khmurovska ◽  
Petr Štemberk ◽  
Svyatoslav Sikorin ◽  
Jiří Němeček ◽  
Daria Jóźwiak-Niedźwiedzka ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Gamma Ray ◽  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mercury Intrusion ◽  
Significant Difference ◽  
Gamma Ray Irradiation ◽  
Control Samples

AbstractThe effect of gamma-ray irradiation on cement mortar properties is investigated in this study in order to understand the mechanism behind the strength and stiffness reduction, which may be significant according to the available researches. 60Co irradiation facility with the generating dose rate of 0.1–10 Gy/s and the total activity of 4.4·1015 Bq (120 kCi) was used to perform the irradiation, so that the total observed dose of the irradiated samples reached the values ranging from 12.0 to 15.0 MGy. An identical set of control samples was placed in the same laboratory conditions away from gamma radiation. The results of nanoindentation, X-ray diffraction analysis and mercury intrusion porosimetry of the irradiated and the control samples are shown and explained in detail in this study. The nanoindentation creep compliance and the nanoindentation elastic modulus of the irradiated and the control samples do not show any significant difference. The mineral composition obtained using the X-ray diffraction analysis of the irradiated and the control samples is also similar. The pore structure rearrangement and microcrack occurrence, which were evidenced by the mercury intrusion porosimetry and scanning electron microscopy, led to the porosity increase and may be attributed to the significant decrease of compressive strength.

scholarly journals Enhancement the Mycosynthesis of Selenium Nanoparticles by Using Gamma Radiation

Dose-Response ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 155932582110593
Author(s):  
Basma H. Amin ◽  
Hanaa Y. Ahmed ◽  
Eman M. El Gazzar ◽  
Monda M. M. Badawy
Keyword(s):  
Gamma Radiation ◽  
Gamma Ray ◽  
Uv Spectroscopy ◽  
Living System ◽  
Selenium Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Different Doses ◽  
Biogenic Selenium Nanoparticles

Selenium is a fundamental trace element of the living system. Microorganisms play a crucial role in the selenium cycle, both in the environment and in life. Biogenic selenium nanoparticles have shown promising prospects for use in medicine as an antioxidant and anticancer agent. In this study, SeNPs were biosynthesized by Penicillium citrinum. The spore suspension which was previously prepared was exposed to different doses of gamma radiation (10, 20, 30, 50, and 60 Gy). SeNPs were then produced by an irradiated P citrinum. UV spectroscopy, transmission electron microscopy, X-ray diffraction, and GSH content were assayed to evaluate the probability of P citrinum synthesizing SeNPs. In conclusion, irradiation of P citrinum by gamma ray enhances the mycosynthesis of SeNPs.

Improved Electrochemical Durability of PtRuAu/C Catalyst Synthesized by Radiolytic Process

2011 ◽  
Vol 1311 ◽  
Author(s):  
Satoru Kageyama ◽  
Akio Murakami ◽  
Satoshi Seino ◽  
Takashi Nakagawa ◽  
Hideo Daimon ◽  
...  
Keyword(s):  
Linear Sweep Voltammetry ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Radiolytic Process ◽  
Significant Difference ◽  
Direct Methanol ◽  
X Ray Absorption ◽  
Methanol Fuel Cell

ABSTRACTNanoparticle catalyst of PtRuAu/C for direct methanol fuel cell anodes was synthesized by a radiolytic process. Its methanol oxidation activity and the electrochemical durability were evaluated by using the linear sweep voltammetry and the cyclic voltammety. The Au addition significantly improved the durability in comparison with PtRu/C catalyst without losing its high activity. The atomic structure was characterized with techniques of the transmission electron microscopy, the X-ray diffraction, the X-ray fluorescence spectroscopy and the X-ray absorption fine structure. These results implied that the arrangement of Pt and Ru atoms in the PtRuAu/C has no significant difference from that without Au, possessing a structure of Pt rich core and PtRu alloy shell. We concluded that the improvement in durability could originate from these PtRu nanoparticles decorated with Au, but not from particles with high Au contents.

scholarly journals SYNTHESIS OF COPPER-BASED NANOPARTICLE CATALYSTS BY DIFFERENT METHODS FOR TOTAL OXIDATION OF VOC

2018 ◽  
Vol 56 (3B) ◽  
pp. 228 ◽  
Author(s):  
Toan Minh Le ◽  
Ha Than Quoc An ◽  
Thien Pham Huu
Keyword(s):  
X Ray Diffraction ◽  
Gas Phase Reactions ◽  
Total Oxidation ◽  
X Ray ◽  
Nanoparticle Catalysts ◽  
Transmission Electron ◽  
Ft Ir ◽  
Non Thermal Plasma ◽  
Oxidation Efficiency ◽  
Al2o3 Catalyst

In this paper, the process of preparing 10 wt.% Cu/g-Al2O3 catalysts was studied by different methods. The changes in structure and texture of the catalysts were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FT-IR). The activities of catalyst were investigated completely oxidized VOC (toluene and n-butanol) on gas-phase reactions over the Cu/g-Al2O3 catalyst. The results were found that influence of the size of copper nanoparticles enhancing copper dispersion and selectivity of the catalyst prepared by non-thermal plasma (NTP) was superior to those obtained from the impregnation (WI) and deposition-precipitation (DP). The total oxidation of VOC to CO2 and H2O was achieved above 275oC. Compared to the WI and DP, the NTP method increased the oxidation efficiency by 15-30%.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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