A Comprehensive Study of Pristine and Calcined f-MWCNTs Functionalized by Nitrogen-Containing Functional Groups

Abstract

We present the study of pristine and calcined f-MWCNTs functionalized by nitrogen-containing functional groups. We focus on the structural and microstructural modification tuned by the previous annealing. However, our primary goal was to analyze the electronic structure and magnetic properties in relation to the structural properties using a multi-technique approach. The studies carried out by X-ray diffraction, XPS, and 57Fe Mössbauer spectrometry revealed the presence of g-Fe nanoparticles, Fe3C, and a-FeOOH as catalyst residues. XPS analysis based on the deconvolution of core level lines confirmed the presence of various nitrogen-based functional groups due to the purification and functionalization process of the nanotubes. The annealing procedure leads to a structural modification mainly associated with removing surface impurities as purification residues. Magnetic studies confirmed a significant contribution of Fe3C as evidenced by a Curie temperature estimated at TC = 452 ± 15K. A slight change in magnetic properties upon annealing was revealed. The detailed studies performed on nanotubes are extremely important for the further synthesis of composite materials based on f-MWCNTs.

Chiral recognition of tryptophan enantiomer based on the electrode modified by polyaniline adsorption bovine serum albumin complex

“…The same conclusion can be drawn from the XPS high‐resolution spectrum. Figure 5C shows significant signal enhancement for C–C/C=C and C=O 24–26 compared with Figure 5B, which is probably due to the presence of a large number of alkyl, unsaturated alkane, and carboxyl ketonic/keto acid groups on the BSA in the composite of APS‐DPANI‐BSA. When comparing Figure 5D with Figure 5E, we see that one new peak for N–H emerged in APS‐DPANI‐BSA, and the decrease of peak intensity for H–N–H and C–N at the same time, which might be due to the formation of an intermolecular bonding (N–H) between APS–DPANI and BSA.…”

“…The standard curve of 0.5-mg/ml BSA solution (pH = 5) (A); the effect of temperature on adsorption capacity of BSA (B) samples at intervals of 4,8,12,16,20,24,28, and 32 h to measure their absorbance values; and then calculate the adsorption amount by using Formula (1) to obtain the adsorption curve (Figure 12B). As can be seen from the figure, the optimal adsorption time was 24 h.…”

Functionalized Multiwalled Carbon Nanotubes for the Improvement of Dispersion Stability in Diesel Fuel‐type for Potential Application as Nano Additives

“…The O1s curve is deconvoluted in two main components, [40] C=O at 531.7 eV and CÀ O at 533.3 eV, a lower signal for CNT-O at 535.8 eV is associated with water adsorbed due to the presence of polar groups. [41,42] As well, the CÀ O bonds decrease from 73.2 to 40.8 %, when the CNT-O is compared with CNT-OLA, as suggested in curve C1s.…”