Comparative Study of the Growth of CNTs on Stainless Steel with and without the External Catalyst

Abstract

Multi-walled carbon nanotubes were synthesized on 316 stainless steel substrate by chemical vapor deposition through two different methods: 1- without use of any external catalyst and using ethylene as the carbon precursor and 2- using ferrocene as an external source of catalyst particles, dissolved in toluene, as the carbon precursor. Carbon nanotubes grown by the two methods were characterized by scanning and transmission electron microscopy and X-ray diffraction methods and were compared subsequently to determine certain characteristics of each method. Good coverage and homogeneity was observed in both cases. However, the carbon layer was thicker and denser in externally catalyzed samples. Two different mechanisms, namely, base and tip modes, were observed for the nanotubes growth, each with particular characteristics stemming from the synthesis methods. Surface nano-features and external catalyst behavior were found to have the dominant role in determining the morphology of carbon filaments in intrinsically and externally catalyzed samples, respectively

The Effect of Electrodeposited PANI on Corrosion Behavior of 316 Stainless Steel Coated by CVD Grown MWCNTs under PEMFC Bipolar Plate Working Condition

“…Therefore, in addition to the porous layer of high surface area CNTs, a kinetic enhancement may also be expected as a result of the active state of the stainless steel surface. Moreover, the surface nanostructure of SS is also modified and as a step of the CNT growth catalysis, restructuring of the surface and particle break-up happens on the SS surface resulting in the transfer of a large number catalyst nanoparticles into and on the CNTs (40,41). The presence of these metallic particles which can act as catalysts sites for PANI deposition along with high surface area of CNTs can together affect the growth rate of the coating.…”

“…CNTs were grown on SS by two different methods as described in detail in previous works; (1) direct growth by CVD method using ethylene as the carbon source ( 40) and (2) continuous feeding of ferrocene catalyst dissolved in toluene as the carbon source (41). Prior to any of the growth procedures, the substrate material, AISI 316 SS plates of the size 15×15×1 mm, were cleaned with successive sonication in acetone and distilled water followed by nitrogen drying.…”

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].…”