Carbon : nickel nanocomposite templates – predefined stable catalysts for diameter-controlled growth of single-walled carbon nanotubes

Abstract

Carbon : nickel (C : Ni) nanocomposite templates (NCTs) were used as catalyst precursors for diameter-controlled growth of single-walled carbon nanotubes (SWCNTs) by chemical vapor deposition (CVD). Two NCT types of 2 nm thickness were prepared by ion beam co-sputtering without (type I) or with assisting Ar(+) ion irradiation (type II). NCT type I comprised Ni-rich nanoparticles (NPs) with defined diameter in an amorphous carbon matrix, while NCT type II was a homogenous C : Ni film. Based on the Raman spectra of more than 600 individual SWCNTs, the diameter distribution obtained from both types of NCT was determined. SWCNTs with a selective, monomodal diameter distribution are obtained from NCT type I. About 50% of the SWCNTs have a diameter of (1.36 ± 0.10) nm. In contrast to NCT type I, SWCNTs with a non-selective, relatively homogeneous diameter distribution from 0.80 to 1.40 nm covering 88% of all SWCNTs are obtained from NCT type II. From both catalyst templates predominantly separated as-grown SWCNTs are obtained. They are free of solvents or surfactants, exhibit a low degree of bundling and contain negligible amounts of MWCNTs. The study demonstrates the advantage of predefined catalysts for diameter-controlled SWCNT synthesis in comparison to in situ formed catalysts.

Phase Transitions in C:Ni Nanocomposite Templates during Diameter‐Selective CVD Synthesis of SWCNTs

“…It can be conservatively estimated that its diameter hardly exceeds 2 nm. Obeying the experimental accuracy this is in good agreement with the diameter distribution maximum found by Raman mapping …”

“…Obeying the experimental accuracy this is in good agreement with the diameter distribution maximum found by Raman mapping. [9] Beyond the formation of SWCNTs, Raman spectroscopy reveals significant changes of the phase structure of the www.advancedsciencenews.com www.pss-b.com embedding carbon matrix ( Figure 3). The spectrum after step 1 has the typical characteristics of amorphous sp 2 -C (a-C) with broad features corresponding to the D, G, and D þ G line ( Figure 3a).…”

“…[27] Later on, p-bonded acetylide-Ni complexes were found as another acetylene-derived species on Ni surfaces. [31] These surface species undergo thermally-induced decomposition of into hydrogen and precipitated carbon at temperatures above 200 C. [27,31,32] Summarizing the presented experimental results and the discussion so far, different forms of carbon as well as of acetylene may act as potential carbon sources for the 2.0 AE 0.3 [9] 2.2 AE 0.4 [9] 3.0 AE 0.7 [9] sp 2 -carbon phase structure a-C this work a-C, sp2-C ring cluster this work SWCNTs [9] , this work NP phase structure rh-Ni 3 C, a-Ni 3 C [9] fcc-NiO this work fcc-Ni, rh-Ni 3 C [9] www.advancedsciencenews.com www.pss-b.com formation of SWCNTs in process step 3. They can be specified as follows:…”

In Situ Observations of Phase Transitions in Metastable Nickel (Carbide)/Carbon Nanocomposites

“…In a wider context, our study also contributes to the elucidation of the recently debated role of Ni 3 C as a possible intermediate bulk catalyst phase in Ni-catalyzed graphene 35 − 44 and carbon nanotube (CNT) 45 − 60 growth. Taking our Ni 3 C/a-C nanocomposites as a model system for graphitization from Ni 3 C, our in situ derived findings suggest that fcc Ni with interstitial carbon dissolved (Ni(-C)), rather than bulk Ni 3 C, is the active catalyst phase during graphitic nanostructure growth under typical chemical vapor deposition (CVD) conditions.…”

Maternal and Fetal Toxicity-Induced by Nickel Oxide Nanoparticles Administration in Albino Rats During Gestation

“…The most widely used types of nanomaterials are the metallic nanoparticles including metallic nickel nanoparticles (Ni NPs). Ni NPs are used in many fields, including magnetic resonance imaging [1], magnetic fluids [2], catalysts [3,4], magnetic recording media [5], solar cells, lithiumion batteries, diodes, and biosensors [6], as well as in urea and glucose sensors [7,8], optoelectronics [9], magnetic hyperthermia [10], and other biomedical applications [11]. Furthermore, Nickel oxide nanoparticles (NiO NPs) have diesel-fuel additive and pigment properties [12].…”