Comparison of x-ray photoelectron spectroscopy and cyclic voltammetry for the determination of polymeric film thickness of ruthenium vinylbipyridine and vinylferrocene deposited on electrodes

1981 ◽  
Vol 53 (8) ◽  
pp. 1170-1175 ◽  
Author(s):  
M. Umana ◽  
P. Denisevich ◽  
D. R. Rolison ◽  
S. Nakahama ◽  
Royce W. Murray
Keyword(s):  
Cyclic Voltammetry ◽  
Film Thickness ◽  
Photoelectron Spectroscopy ◽  
Polymeric Film ◽  
X Ray

A Two-step Electrodeposition of Pd-Cu/Cu2O Nanocomposite on FTO Substrate for Non-enzymatic Hydrogen Peroxide Sensor

2021 ◽  
Vol 17 ◽  
Author(s):  
Ke Huan ◽  
Li Tang ◽  
Dongmei Deng ◽  
Huan Wang ◽  
Xiaojing Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Pd Nanoparticles ◽  
Optimal Conditions ◽  
Potential Oscillation ◽  
X Ray Diffraction ◽  
X Ray

Background: Hydrogen peroxide (H2O2) is a common reagent in the production and living, but excessive H2O2 may enhance the danger to the human body. Consequently, it is very important to develop economical, fast and accurate techniques for detecting H2O2. Methods: A simple two-step electrodeposition process was applied to synthesize Pd-Cu/Cu2O nanocomposite for non-enzymatic H2O2 sensor. Cu/Cu2O nanomaterial was firstly electrodeposited on FTO by potential oscillation technique, and then Pd nanoparticles were electrodeposited on Cu/Cu2O nanomaterial by cyclic voltammetry. The chemical structure, component, and morphology of the synthesized Pd-Cu/Cu2O nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties of Pd-Cu/Cu2O nanocomposite were studied by cyclic voltammetry and amperometry. Results: Under optimal conditions, the as-fabricated sensor displayed a broad linear range (5-4000 µM) and low detection limit (1.8 µM) for the determination of H2O2. The proposed sensor showed good selectivity and reproducibility. Meanwhile, the proposed sensor has been successfully applied to detect H2O2 in milk. Conclusion: The Pd-Cu/Cu2O/FTO biosensor exhibits excellent electrochemical activity for H2O2 reduction, which has great potential application in the field of food safety.

Accurate determination of SiO2 film thickness by x-ray photoelectron spectroscopy

2003 ◽  
Vol 83 (16) ◽  
pp. 3422-3424 ◽  
Author(s):  
K. Takahashi ◽  
H. Nohira ◽  
K. Hirose ◽  
T. Hattori
Keyword(s):  
Film Thickness ◽  
Photoelectron Spectroscopy ◽  
Accurate Determination ◽  
Sio2 Film ◽  
X Ray

scholarly journals Optical Constant and Conformality Analysis of SiO2 Thin Films Deposited on Linear Array Microstructure Substrate by PECVD

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 510
Author(s):  
Yongqiang Pan ◽  
Huan Liu ◽  
Zhuoman Wang ◽  
Jinmei Jia ◽  
Jijie Zhao
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Deposition Rate ◽  
Optical Constant ◽  
Photoelectron Spectroscopy ◽  
Linear Array ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
X Ray ◽  
Sio2 Thin Film

SiO2 thin films are deposited by radio frequency (RF) plasma-enhanced chemical vapor deposition (PECVD) technique using SiH4 and N2O as precursor gases. The stoichiometry of SiO2 thin films is determined by the X-ray photoelectron spectroscopy (XPS), and the optical constant n and k are obtained by using variable angle spectroscopic ellipsometer (VASE) in the spectral range 380–1600 nm. The refractive index and extinction coefficient of the deposited SiO2 thin films at 500 nm are 1.464 and 0.0069, respectively. The deposition rate of SiO2 thin films is controlled by changing the reaction pressure. The effects of deposition rate, film thickness, and microstructure size on the conformality of SiO2 thin films are studied. The conformality of SiO2 thin films increases from 0.68 to 0.91, with the increase of deposition rate of the SiO2 thin film from 20.84 to 41.92 nm/min. The conformality of SiO2 thin films decreases with the increase of film thickness, and the higher the step height, the smaller the conformality of SiO2 thin films.

scholarly journals An Insight into Chemistry and Structure of Colloidal 2D-WS2 Nanoflakes: Combined XPS and XRD Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1969
Author(s):  
Riccardo Scarfiello ◽  
Elisabetta Mazzotta ◽  
Davide Altamura ◽  
Concetta Nobile ◽  
Rosanna Mastria ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Xrd Analysis ◽  
Crystal Habit ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Evaluation ◽  
Rational Understanding ◽  
Structural Inspection

The surface and structural characterization techniques of three atom-thick bi-dimensional 2D-WS2 colloidal nanocrystals cross the limit of bulk investigation, offering the possibility of simultaneous phase identification, structural-to-morphological evaluation, and surface chemical description. In the present study, we report a rational understanding based on X-ray photoelectron spectroscopy (XPS) and structural inspection of two kinds of dimensionally controllable 2D-WS2 colloidal nanoflakes (NFLs) generated with a surfactant assisted non-hydrolytic route. The qualitative and quantitative determination of 1T’ and 2H phases based on W 4f XPS signal components, together with the presence of two kinds of sulfur ions, S22− and S2−, based on S 2p signal and related to the formation of WS2 and WOxSy in a mixed oxygen-sulfur environment, are carefully reported and discussed for both nanocrystals breeds. The XPS results are used as an input for detailed X-ray Diffraction (XRD) analysis allowing for a clear discrimination of NFLs crystal habit, and an estimation of the exact number of atomic monolayers composing the 2D-WS2 nanocrystalline samples.

scholarly journals Graphitic Nitrogen in Carbon Catalysts Important for the Reduction of Nitrite Revealed by 15N NMR Spectroscopy at Natural Abundance

2020 ◽  
Author(s):  
Zheng Chen ◽  
Aleksander Jaworski ◽  
Jianhong Chen ◽  
Tetyana Budnyak ◽  
Ireneusz Szewczyk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
Nitrite Reduction ◽  
15N Nmr ◽  
Carbon Catalyst ◽  
X Ray ◽  
Wide Range ◽  
Alkaline Conditions

Metal-free nitrogen-doped carbon is considered as a green functional material, but the structural determination of the atomic positions of nitrogen remains challenging. We recently demonstrated that directly-excited solid state <sup>15</sup>N NMR (ssNMR) spectroscopy is a powerful tool for the determination of such positions in an N-doped carbon at natural <sup>15</sup>N isotope abundance. Here we present a green chemistry approach to the synthesis of N-doped carbon using cellulose as precursor, and a study of the catalytic properties and atomic structures of the related catalyst. The N-doped carbon (NH<sub>3</sub>) was obtained by oxidation of cellulose with HNO<sub>3</sub> followed by ammonolysis at 800°C. It had a N content of 6.5 wt.% and a surface area of 557 m<sup>2 </sup>g<sup>–1</sup>, and <sup>15</sup>N ssNMR spectroscopy provided evidence for graphitic nitrogen besides of regular pyrrolic and pyridinic nitrogen. This structure determination enabled probing the role of graphitic nitrogen for electrocatalytic reactions, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and nitrite reduction reaction. The N-doped carbon catalyst (NH<sub>3</sub>) had higher electrocatalytic activities in OER and HER under alkaline conditions and a higher activity for nitrite reduction, as compared with a catalyst prepared by carbonization of the HNO<sub>3</sub>-treated cellulose in N<sub>2</sub>. The electrocatalytic selectivity for nitrite reduction of the N-doped carbon catalyst (NH<sub>3</sub>) was directly related to the graphitic nitrogen functions. Complementary structural analysis by means of <sup>13</sup>C and <sup>1</sup>H ssNMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature N<sub>2 </sub>adsorption were preformed and provided support to the findings. The results show that directly-excited <sup>15</sup>N ssNMR at natural <sup>15</sup>N abundance is generally capable to provide information on N-doped carbon materials, and it is expected that the approach can be applied to a wide range of solids with an intermediate amount of N atoms.

Tailoring surface properties of functionalized graphene papers aiming to enzyme immobilization

2021 ◽  
Author(s):  
Jéssica Luzardo ◽  
Douglas Aguiar ◽  
Alexander Silva ◽  
Sanair Oliveira ◽  
Braulio Archanjo ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Enzyme Stability ◽  
Immobilized Enzymes ◽  
Free Enzyme ◽  
X Ray ◽  
Force Microscopy ◽  
Enzyme Solution ◽  
Atomic Force ◽  
Composition And Structure

The use of enzymes as catalysts requires recovery and reuse to make the process viable. Enzymatic immobilization changes enzyme stability, activity, and specificity. It is very important to explore new substrates for immobilization with appropriate composition and structure to improve the efficiency of the immobilized enzymes. This work explores the use of two different graphene oxide papers, one produced by oxidation route (GO) and the other by electrochemical synthesis (EG), aiming for β-galactosidase immobilization. The chemical and structural properties of these two papers were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Atomic force microscopy images showed that EG paper ensured more efficient immobilization of the enzymes on the surface of the paper. Cyclic voltammetry was used to monitor the reaction of conversion of lactose to glucose in the free enzyme solution and graphene paper immobilized enzyme solutions. The cyclic voltammetry analysis showed that immobilized enzymes on GO paper showed an improvement in the activity of β-galactose when compared to free enzyme solution, as well as enzyme immobilized on a glassy carbon electrode.

Sign in / Sign up

Export Citation Format

Share Document