Improvement of methanol oxidation catalytic activities of radiochemically synthesized PtRu/C nanoparticles by post annealing process

2014 ◽  
Vol 1641 ◽  
Author(s):  
Satoshi Seino ◽  
Masato Morisue ◽  
Yuji Ohkubo ◽  
Junichiro Kugai ◽  
Takashi Nakagawa ◽  
...  
Keyword(s):  
Methanol Oxidation ◽  
Material Characterization ◽  
Annealing Temperature ◽  
High Energy ◽  
Redox Potentials ◽  
Catalytic Activities ◽  
Oxidation Current ◽  
Post Annealing ◽  
Radiochemical Process ◽  
Ptru Nanoparticles

ABSTRACTElectrode catalysts composed of carbon supported PtRu nanoparticles (PtRu/C) synthesized by radiochemical process were annealed to control the PtRu substructure to enhance catalytic activity. The substructure of the PtRu nanoparticles synthesized by using high-energy electron beam under acidic condition was Pt-rich core/Ru-rich shell type, reflecting the redox potentials of each precursor ions. The material characterization techniques revealed that the reductive annealing led to the mixing of PtRu both in the core and on the surface. The sample with annealing temperature of 300°C for 5 hour showed the highest methanol oxidation current, 2.3 times higher than that obtained with before annealing.

Preparation of Platinum-Ruthenium Nanoparticles on Graphite Nanofibers

2008 ◽  
Vol 135 ◽  
pp. 39-42 ◽  
Author(s):  
Seok Kim ◽  
Soo Jin Park
Keyword(s):  
Particle Size ◽  
Methanol Oxidation ◽  
Deposition Time ◽  
Particle Dispersion ◽  
Ruthenium Nanoparticles ◽  
Size Particle ◽  
Oxidation Current ◽  
Graphite Nanofibers ◽  
Ptru Catalysts ◽  
Ptru Nanoparticles

Electroactivity of graphite nanofibers (GNFs)-supported PtRu particles was examined for their application as DMFCs anode. In this work, composites of PtRu nanoparticles of 2-8 nm size and graphite nanofibers were prepared by the electrodeposition methods. As a result, the methanol oxidation current for graphite nanofibers-supported PtRu catalysts was investigated by changing a deposition time. The electroactivity could be attributed to the particle size, particle dispersion ability, and deposition level.

Structural change by high-energy ion irradiation and post-annealing in EuBa2Cu3Oy

2002 ◽  
Vol 378-381 ◽  
pp. 527-530 ◽  
Author(s):  
H Sato ◽  
N Ishikawa ◽  
A Iwase ◽  
Y Chimi ◽  
T Hashimoto ◽  
...  
Keyword(s):  
Structural Change ◽  
Ion Irradiation ◽  
High Energy ◽  
Post Annealing

scholarly journals Optimizing the Properties of La0.8Sr0.2CrO3 Thin Films through Post-Annealing for High-Temperature Sensing

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1802
Author(s):  
Dan Liu ◽  
Peng Shi ◽  
Yantao Liu ◽  
Yijun Zhang ◽  
Bian Tian ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Annealing Temperature ◽  
Rf Sputtering ◽  
Maximum Size ◽  
Cross Sectional ◽  
Post Annealing ◽  
Maximum Conductivity ◽  
Different Temperatures ◽  
Post Annealing Temperature

La0.8Sr0.2CrO3 (0.2LSCO) thin films were prepared via the RF sputtering method to fabricate thin-film thermocouples (TFTCs), and post-annealing processes were employed to optimize their properties to sense high temperatures. The XRD patterns of the 0.2LSCO thin films showed a pure phase, and their crystallinities increased with the post-annealing temperature from 800 °C to 1000 °C, while some impurity phases of Cr2O3 and SrCr2O7 were observed above 1000 °C. The surface images indicated that the grain size increased first and then decreased, and the maximum size was 0.71 μm at 1100 °C. The cross-sectional images showed that the thickness of the 0.2LSCO thin films decreased significantly above 1000 °C, which was mainly due to the evaporation of Sr2+ and Cr3+. At the same time, the maximum conductivity was achieved for the film annealed at 1000 °C, which was 6.25 × 10−2 S/cm. When the thin films post-annealed at different temperatures were coupled with Pt reference electrodes to form TFTCs, the trend of output voltage to first increase and then decrease was observed, and the maximum average Seebeck coefficient of 167.8 µV/°C was obtained for the 0.2LSCO thin film post-annealed at 1100 °C. Through post-annealing optimization, the best post-annealing temperature was 1000 °C, which made the 0.2LSCO thin film more stable to monitor the temperatures of turbine engines for a long period of time.

scholarly journals Structural Studies of Zno Nanostructures on Porous Silicon: Effect of Post-Annealing Temperature

2018 ◽  
Vol 7 (3.11) ◽  
pp. 48
Author(s):  
Kevin Alvin Eswar ◽  
Mohd Husairi Fadzillah Suhaimi ◽  
Muliyadi Guliling ◽  
Zuraida Khusaimi ◽  
Mohamad Rusop ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Annealing Temperature ◽  
Electrochemical Etching ◽  
Texture Coefficient ◽  
Zno Nanostructures ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Post Annealing ◽  
Post Annealing Temperature

ZnO Nanostructures have been successfully deposited on of Porous silicon (PSi) via wet colloid chemical approach. PSi was prepared by electrochemical etching method. ZnO/PSi thin films were annealed in different temperature in the range of 300 °C to 700 °C. Surface morphology studies were conducted using field emission scanning microscopy (FESEM). Flower-like structures of ZnO were clearly seen at annealing temperature of 500 °C. The X-ray diffraction spectra (XRD) have been used to investigate the structural properties. There are three dominant peaks referred to plane (100), (002) and (101) indicates that ZnO has a polycrystalline hexagonal wurtzite structures. Plane (002) shows the highest intensities at annealing temperature of 500 °C. Based on plane (002) analysis, the sizes were in range of 30.78 nm to 55.18. In addition, it was found that the texture coefficient of plane (002) is stable compared to plane (100) and (101). 

Influence of Post-Annealing Temperature on the Material Properties of Zinc Oxide Nanorods

2010 ◽  
Vol 10 (10) ◽  
pp. 6419-6423 ◽  
Author(s):  
Sharul Ashikin Kamaruddin ◽  
Mohd Zainizan Sahdan ◽  
Kah-Yoong Chan ◽  
Mohamad Rusop ◽  
Hashim Saim
Keyword(s):  
Zinc Oxide ◽  
Material Properties ◽  
Annealing Temperature ◽  
Zinc Oxide Nanorods ◽  
Post Annealing ◽  
Oxide Nanorods ◽  
Post Annealing Temperature

Effect of Annealing on Structural and Optical Properties of Pulsed Laser Deposited Titanium Dioxide Thin Films

2009 ◽  
Vol 67 ◽  
pp. 65-70 ◽  
Author(s):  
Gaurav Shukla ◽  
Alika K. Khare
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Pulsed Laser Deposition ◽  
Annealing Temperature ◽  
Ambient Pressure ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Tio2 Thin Films ◽  
Post Annealing ◽  
Post Annealing Temperature

TiO2 is a widely studied material for many important applications in areas such as environmental purification, photocatalyst, gas sensors, cancer therapy and high effect solar cell. However, investigations demonstrated that the properties and applications of titanium oxide films depend upon the nature of the crystalline phases present in the films, i.e. anatase and rutile phases. We report on the pulsed laser deposition of high quality TiO2 thin films. Pulsed Laser deposition of TiO2 thin films were performed in different ambient viz. oxygen, argon and vacuum, using a second harmonic of Nd:YAG laser of 6 ns pulse width. These deposited films of TiO2 were further annealed for 5hrs in air at different temperatures. TiO2 thin films were characterized using x-ray diffraction, SEM, photoluminescence, transmittance and reflectance. We observed effect of annealing over structural, morphological and optical properties of TiO2 thin films. The anatase phase of as-deposited TiO2 thin films is found to change into rutile phase with increased annealing temperature. Increase in crystalline behaviour of thin films with post-annealing temperature is also observed. Surface morphology of TiO2 thin films is dependent upon ambient pressure and post- annealing temperature. TiO2 thin films are found to be optically transparent with very low reflectivity hence will be suitable for antireflection coating applications.

Experimental Analysis and Material Characterization of Ultra High Temperature Composites

2021 ◽  
Author(s):  
Anindya Ghoshal ◽  
Michael J. Walock ◽  
Andy Nieto ◽  
Muthuvel Murugan ◽  
Clara Hofmeister-Mock ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Material Characterization ◽  
High Energy ◽  
Test Material ◽  
Layer System ◽  
Vannevar Bush ◽  
Sic Composites ◽  
Ultra High Temperature

Abstract Ultra high temperature ceramic (UHTC) materials have attracted attention for hypersonic applications. Currently there is significant interest in possible gas turbine engine applications of UHTC composites as well. However, many of these materials, such as hafnium carbide, zirconium carbide, and zirconium diboride, have significant oxidation resistance and toughness limitations. In addition, these materials are very difficult to manufacture because of their high melting points. In many cases, SiC powder is incorporated into UHTCs to aid in processing and to enhance fracture toughness. This can also improve the materials’ oxidation resistance at moderately high temperatures due to a crack-healing borosilicate phase. ZrB2-SiC composites show very good oxidation resistance up to 1700 °C, due to the formation of SiO2 and ZrO2 scales in numerous prior studies. While this may limit its application to hypersonic applications (due to reduced thermal conductivity and oxidation resistance at higher temperatures), these UHTC-SiC composites may find applications in turbomachinery, as either stand-alone parts or as a component in a multi-layer system. The US Army Research Laboratory (ARL), the Naval Postgraduate School (NPS), and the University of California – San Diego (UCSD) are developing tough UHTC composites with high durability and oxidation resistance. For this paper, UHTC-SiC composites and high-entropy fluorite oxides were developed using planetary and high-energy ball milling and consolidated using spark plasma sintering. These materials were evaluated for their oxidation-resistance, ablation-resistance, and thermal cycling behavior under a DoD/OSD-funded Laboratory University Collaborative Initiative (LUCI) Fellowship and DoD Vannevar Bush Fellowship Program. In the present paper experimental results and post-test material characterization of SPS sintered ZrB2, ZrB2+SiC, ZrB2+SiC+HfC, HfC+SiC, and HfC+ZrB2 pellets subjected to ablation test are presented.

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