Volumetric distribution of Pt nanoparticles supported on mesoporous carbon substrates studied by X-ray photoelectron spectroscopy depth profiling

Carbon ◽  
2013 ◽  
Vol 54 ◽  
pp. 389-395 ◽  
Author(s):  
Hsiu-Chu Wu ◽  
Chih-Ching Chang ◽  
Hui-Ping Tseng ◽  
Kang-Ning Lee ◽  
Cheng-Hsiang Tung ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Depth Profiling ◽  
Pt Nanoparticles ◽  
X Ray ◽  
Carbon Substrates

A Label-Free Electrochemical Aptasensor for the Rapid Detection of Tetracycline Based on Ordered Mesoporous Carbon–Fe3O4

2018 ◽  
Vol 71 (3) ◽  
pp. 170 ◽  
Author(s):  
Xuejia Zhan ◽  
Guangzhi Hu ◽  
Thomas Wagberg ◽  
Dongwei Zhang ◽  
Pei Zhou
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Physical Adsorption ◽  
Differential Pulse ◽  
Ordered Mesoporous Carbon ◽  
Label Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ordered Mesoporous ◽  
Modification Procedure

A novel aptasensor based on a tetracycline (TET) aptamer immobilized by physical adsorption on an ordered mesoporous carbon–Fe3O4 (OMC-Fe3O4)-modified screen-printed electrode surface was successfully fabricated. OMC-Fe3O4 was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The modification procedure of the aptasensor was characterized by cyclic voltammetry. Interaction between the TET aptamer and target was determined by differential pulse voltammetry. Under optimal conditions, the proposed aptasensor exhibited good electrochemical sensitivity to TET in a concentration range of 5 nM to 10 μM, with a detection limit of 0.8 nM (S/N = 3). This aptasensor exhibited satisfactory specificity, reproducibility, and stability.

Uniform Depth Profiling in X-ray Photoelectron Spectroscopy (Electron Spectroscopy for Chemical Analysis)

1978 ◽  
Vol 32 (2) ◽  
pp. 175-177 ◽  
Author(s):  
L. Bradley ◽  
Y. M. Bosworth ◽  
D. Briggs ◽  
V. A. Gibson ◽  
R. J. Oldman ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Auger Electron Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Depth Profiling ◽  
Ion Source ◽  
X Ray ◽  
Nitride Oxide ◽  
Silicon Device

The difficulties of nonuniform ion etching which hamper depth profiling by X-ray photoelectron spectroscopy (XPS) have been overcome by use of a mechanically scanned saddle-field ion source. The system and its calibration for uniformity are described, and its performance is illustrated by the depth profile of a Si3N4/SiO2/Si metal nitride oxide silicon device. This also allows the potential advantages of XPS profiling over Auger electron spectroscopy profiling to be discussed.

CVD Boron Carbo-Nitride as Pore Sealant for Ultra Low-K Interlayer Dielectrics

2005 ◽  
Vol 863 ◽  
Author(s):  
P. Ryan Fitzpatrick ◽  
Sri Satyanarayana ◽  
Yangming Sun ◽  
John M. White ◽  
John G. Ekerdt
Keyword(s):  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Chemical Vapor ◽  
K Value ◽  
X Ray ◽  
Dimethylamine Borane ◽  
The Stability ◽  
Low K ◽  
Secondary Ion ◽  
Sims Depth Profiling

AbstractBlanket porous methyl silsesquioxane (pMSQ) films on a Si substrate were studied with the intent to seal the pores and prevent penetration of a metallic precursor during barrier deposition. The blanket pMSQ films studied were approximately 220 nm thick and had been etched and ashed. When tantalum pentafluoride (TaF5) is exposed to an unsealed pMSQ sample, X-ray photoelectron spectroscopy (XPS) depth profiling and secondary ion mass spectroscopy (SIMS) depth profiling reveal penetration of Ta into the pores all the way to the pMSQ / Si interface. Boron carbo-nitride films were grown by thermal chemical vapor deposition (CVD) using dimethylamine borane (DMAB) precursor with Ar carrier gas and C2H4 coreactant. These films had a stoichiometry of BC0.9N0.07 and have been shown in a previous study to have a k value as low as 3.8. BC0.9N0.07 films ranging from 1.8 to 40.6 nm were deposited on pMSQ and then exposed to TaF5 gas to determine the extent of Ta penetration into the pMSQ. Ta penetration was determined by XPS depth profiling and sometimes SIMS depth profiling. XPS depth profiling of a TaF5 / 6.3 nm BC0.9N0.07 / pMSQ / Si film stack indicates the attenuation of the Ta signal to < 2 at. % throughout the pMSQ. Backside SIMS of this sample suggests that trace amounts of Ta (< 2 at. %) are due to knock-in by Ar ions used for sputtering. An identical film stack containing 3.9 nm BC0.9N0.07 was also successful at inhibiting Ta penetration even with a 370°C post-TaF5 exposure anneal, suggesting the stability of BC0.9N0.07 to thermal diffusion of Ta. All BC0.9N0.07 films thicker than and including 3.9 nm prevented Ta from penetrating into the pMSQ.

scholarly journals Depth Profiling of the Chemical Composition of Free-Standing Carbon Dots Using X-ray Photoelectron Spectroscopy

2018 ◽  
Vol 122 (26) ◽  
pp. 14889-14897 ◽  
Author(s):  
Irene Papagiannouli ◽  
Minna Patanen ◽  
Valérie Blanchet ◽  
John D. Bozek ◽  
Manuel de Anda Villa ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Carbon Dots ◽  
Depth Profiling ◽  
Free Standing ◽  
X Ray

Sub-nm-Scale Depth Profiling of Nitrogen in NO- and N2-Annealed SiO2/4H-SiC(0001) Structures

2019 ◽  
Vol 963 ◽  
pp. 226-229
Author(s):  
Kidist Moges ◽  
Mitsuru Sometani ◽  
Takuji Hosoi ◽  
Takayoshi Shimura ◽  
Shinsuke Harada ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Annealing Duration ◽  
Nanometer Scale ◽  
Pure Nitrogen ◽  
X Ray ◽  
Initial Stage

We demonstrated an x-ray photoelectron spectroscopy (XPS)-based technique to reveal the detailed nitrogen profile in nitrided SiO2/4H-SiC structures with sub-nanometer-scale-resolution. In this work, nitric oxide (NO)- and pure nitrogen (N2)-annealed SiO2/4H-SiC(0001) structures were characterized. The measured results of NO-annealed samples with various annealing duration indicate that preferential nitridation just at the SiO2/SiC interfaces (~0.3 nm) proceeds in the initial stage of NO annealing and a longer duration leads to the distribution of nitrogen in the bulk SiO2 within few nanometers of the interface. The high-temperature N2 annealing was found to induce not only SiO2/SiC interface nitridation similarly to NO annealing but also SiO2 surface nitridation.

scholarly journals Copper microsphere hybrid mesoporous carbon as matrix for preparation of shape-stabilized phase change materials with improved thermal properties

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yi Liu ◽  
Yan Chen ◽  
Junwei Zhang ◽  
Junkai Gao ◽  
Zhi Han
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Phase Change Materials ◽  
Copper Ions ◽  
Thermal Constant ◽  
Step Method ◽  
Scanning Calorimetry ◽  
X Ray

Abstract Copper microsphere hybrid mesoporous carbon (MPC-Cu) was synthesized by the pyrolysis of polydopamine microspheres doped with copper ions that were prepared using a novel, facile and simple one-step method of dopamine biomimetic polymerization and copper ion adsorption. The resulting MPC-Cu was then used as a supporter for polyethylene glycol (PEG) to synthesize shape-stabilized phase change materials (PEG/MPC-Cu) with enhanced thermal properties. PEG/MPC-Cu was studied by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, differential scanning calorimetry and thermal constant analysis. The results demonstrated that the thermal conductivity of PEG/MPC-Cu was 0.502 W/(m K), which increased by 100% compared to pure PEG [0.251 W/(m K)]. The melting enthalpy of PEG/MPC-Cu was 95.98 J/g, indicating that PEG/MPC-Cu is a promising candidate for future thermal energy storage applications. In addition, the characterization results suggested that PEG-MPC-Cu possessed high thermal stability. Therefore, the method developed in this paper for preparing shape-stabilized phase change materials with improved thermal properties has substantial engineering application prospects.

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.

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