In situ FTIR and Raman spectroelectrochemical characterization of graphene oxide upon electrochemical reduction in organic solvents

2015 ◽  
Vol 17 (18) ◽  
pp. 12115-12123 ◽  
Author(s):  
Antti Viinikanoja ◽  
Jussi Kauppila ◽  
Pia Damlin ◽  
Milla Suominen ◽  
Carita Kvarnström

Spectroelectrochemical methods confirmed structural rearrangement and loss of oxygen-containing functional groups of graphene oxide during the electrochemical reduction in organic solvents.

2015 ◽  
Author(s):  
Murugan Veerapandian ◽  
Suresh Neethirajan

Hybridization of distinct materials into a single nanoplatform is relevant to advance material’s properties for functional application such as biosensor platform. We report the synthesis and characterization of nanosheets of graphene oxide decorated with hybrid nanoparticles of silver-ruthenium bipyridine complex (Ag@[Ru(bpy)3]2+) core and chitosan shell. Hybrid nanoparticles were first obtained through a sequential wet-chemical approach using in situ reduction, electrostatic and coordination reaction. Oxygenated functional groups of graphene oxide and abundant amine groups of chitosan layer on the surface of hybrid nanoparticles allowed the functionalization reaction. Changes in intrinsic optical, chemical and structural properties of graphene oxide due to hybrid nanoparticles were studied in depth using spectroscopic techniques and an electron microscope. Electrodes modified with nanosheets of graphene oxide-hybrid nanoparticles retain the biocompatibility and displayed an amplified redox property suitable for a broad range of sensing studies.


2007 ◽  
Vol 127 (1-4) ◽  
pp. 189-198 ◽  
Author(s):  
Oleg S. Alexeev ◽  
Sundaram Krishnamoorthy ◽  
Cody Jensen ◽  
Michael S. Ziebarth ◽  
George Yaluris ◽  
...  

2019 ◽  
pp. 089270571988909
Author(s):  
Sedigheh Khalili ◽  
Zahra Rafiee

The ternary superparamagnetic nanocomposites consisting of graphene oxide (GO), Fe3O4 nanoparticles, and optically active poly(amide-imide) (PAI) were fabricated in three steps consisting of a facile one-pot in situ growth of Fe3O4 on GO, resulted in the preparation of the magnetic Fe3O4@GO, modification of Fe3O4@GO by 3-aminopropyltriethoxy silane to introduce amino groups on its surface, and subsequently its compositing by various levels of 5, 10, and 15 wt% with chiral PAI derived from 3,5-diamino- N-(4-(di(1H-indol-3-yl)methyl)phenyl)benzamide and N, N′-(4,4′-carbonyldiphthaloyl)-bis-l-phenylalanine diacid through ultrasonic irradiation. Characterization of the resulting nanocomposites was performed by Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, scanning electron microscope (SEM), and thermogravimetric analysis (TGA). The SEM analysis showed Fe3O4 nanoparticles with 30 nm size successfully decorated the GO nanosheets. The TGA analysis established the expected thermal stabilities for PAI/Fe3O4@GO nanocomposites. Furthermore, incorporation of Fe3O4@GO in polymer matrix improved the mechanical properties substantially. PAI/Fe3O4@GO 10 wt% was used to evaluate the sorption properties of Hg2+ at pH 7.


Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 123 ◽  
Author(s):  
Andrea Bellmann ◽  
Christine Rautenberg ◽  
Ursula Bentrup ◽  
Angelika Brückner

UV–Vis spectroscopy as well as in situ FTIR spectroscopy of pyridine and CO adsorption were applied to determine the nature of Co species in microporous, mesoporous, and mixed oxide materials like Co–ZSM-5, Co/Na–ZSM-5, Co/Al–SBA-15, and Co/Al2O3–SiO2. Because all sample types show comparable UV–Vis spectra with a characteristic band triplet, the former described UV–Vis band deconvolution method for determination and quantification of individual cationic sites in the zeolite appears doubtful. This is also confirmed by results of pyridine and CO adsorption revealing that all Co–zeolite samples contain two types of Co2+ species located at exchange positions as well as in oxide-like clusters independent of the Co content, while in Co/Al–SBA-15 and Co/Al2O3–SiO2 only Co2+ species in oxide-like clusters occur. Consequently, the measured UV–Vis spectra represent not exclusively isolated Co2+ species, and the characteristic triplet band is not only related to γ-, β-, and α-type Co2+ sites in the zeolite but also to those dispersed on the surface of different oxide supports. The study demonstrates that for proper characterization of the formed Co species, the use of complementary methods is required.


2016 ◽  
Vol 22 (7) ◽  
pp. 2247-2252 ◽  
Author(s):  
Sai Sun ◽  
Xiaodong Zhuang ◽  
Bo Liu ◽  
Luxing Wang ◽  
Linfeng Gu ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jianjun Chen ◽  
Yueyue Jia ◽  
Zhiye Zhang ◽  
Xinlong Wang ◽  
Lin Yang

We investigated the changes in the conformation and crystalline structure of polypropylene (PP) using a combination of Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) based on PP/chlorinated PP (CPP)/polyaniline (PANI) composites. The DSC heating thermograms and WAXD patterns of the PP/CPP/PANI composites showed that theβ-crystal was affected greatly by the CPP content. Characterization of the specific regularity in the infrared band variation showed that the conformational orders of the helical sequences in PP exhibited major changes that depended on the CPP content. Initially, the intensity ratio ofA840/A810increased with the CPP concentration and reached its maximum level when the CPP content was <13.22% before decreasing as the CPP content increased further. The effect of increased temperature on the conformation of PP was studied by in situ FTIR. Initially, the intensity ratio ofA999/A973decreased slowly with increasing the temperature up to 105°C before decreasing sharply with further increases in temperature and then decreasing slowly again when the temperature was higher than 128°C.


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