Insights into the Electronic Structure of Fe Penta-Coordinated Complexes. Spectroscopic Examination and Electrochemical Analysis for the Oxygen Reduction and Oxygen Evolution Reactions.

2021 ◽  
Author(s):  
César Zúñiga-Loyola ◽  
Gabriel Abarca ◽  
Maria Soledad Ureta-Zanartu ◽  
Carolina Aliaga ◽  
Jose Zagal ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Oxygen Reduction ◽  
Oxygen Evolution ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Analysis ◽  
X Ray ◽  
Spectroscopic Examination ◽  
Modified Carbon Nanotubes

Fe phthalocyanine was coordinated to pyridine-modified carbon nanotubes and studied as a catalyst for the oxygen reduction (ORR) and oxygen evolution reactions (OER). X-ray Photoelectron Spectroscopy (XPS), Mössbauer, and Electron...

scholarly journals Nitrogen-Doped Porous Carbon Derived from Biomass Used as Trifunctional Electrocatalyst toward Oxygen Reduction, Oxygen Evolution and Hydrogen Evolution Reactions

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 76 ◽  
Author(s):  
Chinnusamy Sathiskumar ◽  
Shanmugam Ramakrishnan ◽  
Mohanraj Vinothkannan ◽  
Ae Rhan Kim ◽  
Srinivasan Karthikeyan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxygen Reduction ◽  
Hydrogen Evolution ◽  
Oxygen Evolution ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Energy Storage And Conversion ◽  
X Ray ◽  
Metal Free ◽  
Hydrogen Evolution Reactions

Tremendous developments in energy storage and conversion technologies urges researchers to develop inexpensive, greatly efficient, durable and metal-free electrocatalysts for tri-functional electrochemical reactions, namely oxygen reduction reactions (ORRs), oxygen evolution reactions (OERs) and hydrogen evolution reactions (HERs). In these regards, this present study focuses upon the synthesis of porous carbon (PC) or N-doped porous carbon (N-PC) acquired from golden shower pods biomass (GSB) via solvent-free synthesis. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies confirmed the doping of nitrogen in N-PC. In addition, morphological analysis via field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) provide evidence of the sheet-like porous structure of N-PC. ORR results from N-PC show the four-electron pathway (average n = 3.6) for ORRs with a Tafel slope of 86 mV dec−1 and a half-wave potential of 0.76 V. For OERs and HERs, N-PC@Ni shows better overpotential values of 314 and 179 mV at 10 mA cm−2, and its corresponding Tafel slopes are 132 and 98 mV dec−1, respectively. The chronopotentiometry curve of N-PC@Ni reveals better stability toward OER and HER at 50 mA cm−2 for 8 h. These consequences provide new pathways to fabricate efficient electrocatalysts of metal-free heteroatom-doped porous carbon from bio-waste/biomass for energy application in water splitting and metal air batteries.

Electronic Structure of Fluorinated Carbon Nanotubes Studied by X‐ray Absorption and Photoelectron Spectroscopy

2008 ◽  
Vol 16 (5-6) ◽  
pp. 335-339
Author(s):  
M. M. Brzhezinskaya ◽  
N. A. Vinogradov ◽  
V. E. Muradyan ◽  
Yu. M. Shul’ga ◽  
A. S. Vinogradov
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Fluorinated Carbon ◽  
X Ray Absorption

scholarly journals Synergistic Effects of Active Sites’ Nature and Hydrophilicity on the Oxygen Reduction Reaction Activity of Pt-Free Catalysts

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 643 ◽  
Author(s):  
Mariangela Longhi ◽  
Camilla Cova ◽  
Eleonora Pargoletti ◽  
Mauro Coduri ◽  
Saveria Santangelo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Carbon Nanostructures ◽  
Active Sites ◽  
Active Material ◽  
Reduction Reaction ◽  
X Ray

This work highlights the importance of the hydrophilicity of a catalyst’s active sites on an oxygen reduction reaction (ORR) through an electrochemical and physico-chemical study on catalysts based on nitrogen-modified carbon doped with different metals (Fe, Cu, and a mixture of them). BET, X-ray Powder Diffraction (XRPD), micro-Raman, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), and hydrophilicity measurements were performed. All synthesized catalysts are characterized not only by a porous structure, with the porosity distribution centered in the mesoporosity range, but also by the presence of carbon nanostructures. In iron-doped materials, these nanostructures are bamboo-like structures typical of nitrogen carbon nanotubes, which are better organized, in a larger amount, and longer than those in the copper-doped material. Electrochemical ORR results highlight that the presence of iron and nitrogen carbon nanotubes is beneficial to the electroactivity of these materials, but also that the hydrophilicity of the active site is an important parameter affecting electrocatalytic properties. The most active material contains a mixture of Fe and Cu.

scholarly journals Oxygen/Carbon Ratio Effects on Surface-Modified Carbon Nanotubes

2008 ◽  
Vol 2 ◽  
pp. 77-84 ◽  
Author(s):  
U.S. Chen ◽  
Heng Yi Su ◽  
Chung Hao Wang ◽  
Han Chang Shih ◽  
Chien Te Hsieh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Simple Method ◽  
X Ray ◽  
Oxygen Treatment ◽  
Gauss Function ◽  
Cnts Surface ◽  
Surface Modified ◽  
Modified Carbon Nanotubes

Carbon nanotubes (CNTs) were functionalized using a simple method of heat treatment under oxygen atmosphere followed by an immersion in a tin nitrate aqueous solution. And well-dispersed SnOx nanodots were decorated on the surface of CNTs. X-ray photoelectron spectroscopy (XPS) analysis showed that the O/C ratio increases with oxygen-treated time. The distribution of carbon-containing functional groups on the CNTs surface, i.e., C−C, C−O, C=O, O−C=O, and π−π* shake up bonds can be identified and deconvoluted by a symmetrical Gauss function. The contact angle of H2O and CNTs is dependent on O/C ration. The relationships between the fraction of carbon-containing functional groups and various oxygen treatment times are also discussed.

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.

A study of the FeX (X=Si, Ge) system electronic structure by X-ray photoelectron spectroscopy

2000 ◽  
Vol 447 (1-3) ◽  
pp. 112-116 ◽  
Author(s):  
I.N. Shabanova ◽  
V.I. Kormilets ◽  
L.D. Zagrebin ◽  
N.S. Terebova
Keyword(s):  
Electronic Structure ◽  
Photoelectron Spectroscopy ◽  
X Ray
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