Probing the structure of Fe nanoparticles in multiwall carbon nanotubes grown on a stainless steel substrate

Abstract

International audienceWe investigated the local order in individual iron nanoparticles (NPs) embedded in carbon nanotubes (CNTs). The NPs directly come from the CNT growth on stainless steel without addition of external metal catalyst. The structural analysis has been obtained through nanoscale transmission extended electron energy loss fine structure (EXELFS) measurements above the iron L2,3 edge. A theoretical simulation of the EXELFS features has been performed within the multiple scattering theory. By comparing the experimental data with the simulations, we found that pure γ-Fe and Fe3C nanoparticles are the catalysts of the CNT synthesis on the stainless steel. Moreover, from the analysis of the fine details of the EXELFS oscillations, we also estimated the value of the fcc Fe NP lattice parameter to be a = 3.61 ± 0.03 Å. This last finding suggests a high magnetic moment of the fcc Fe NPs

Super-hydrophobic multi-walled carbon nanotube coatings for stainless steel

“…Moreover, MWCNTs come with a wide distribution of tube diameters, with average value 58.19 ± 18.35 nm. Also, we have shown in our past works [43][44][45][46] transmission electron microscopy (TEM) images confirming the multi-walled nature of the as-grown carbon nanotubes. Furthermore, in figures 1(b), (d) it may be observed that MWCNTs are mostly capped and often they present carbonaceous nanostructures (amorphous and/or graphitic carbon) around the tips (figure 1(d)) and close to the stainless steel surface (figure 1(c)), with a characteristic dimension of 100 nanometers, as also reported by other authors [42].…”

“…Recently, we have shown [43][44][45][46] that the direct growth of high quality MWCNTs on stainless steel in the absence of any external catalysts is possible. Moreover, acid treatments and oxidation-reduction stages on this type of surface are not necessary because of the native nano-scale roughness of the substrate and the iron-rich substrate surface both act as an efficient catalyst or template in the synthesis of MWCNTs.…”

Development of a multifunctional TiO2/MWCNT hybrid composite grafted on a stainless steel grating

“…The possible View Article Online conversion of Fe during thermal treatments or the synthesis of CNTs is documented in some papers. 45,[50][51][52] In Fig. 1c and in the corresponding inset, the 2q z 24.6 -25.6 feature, due to the formation of the TiO 2 phase (anatase), is also observed.…”

Effects of CVD direct growth of carbon nanotubes and nanofibers on microstructure and electrochemical corrosion behavior of 316 stainless steel

“…From this standpoint, stainless steel, as an economic material with a high content of iron as the catalyst for CNT synthesis, is an interesting candidate. In fact, several groups have conducted research on direct growth of CNT on stainless steel [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Generally, the interest behind this area of research is multiple, including electrodes for supercapacitors [24][25][26], sensor technology [27][28][29][30], fuel cells [31,32], batteries [33], catalyst support for wastewater treatment [10], field emission probes [34][35][36][37][38] and low friction applications [39][40][41].…”