Low‐Temperature Growth of Carbon Nanotubes Catalyzed by Sodium‐Based Ingredients

Abstract

Synthesis of low‐dimensional carbon nanomaterials such as carbon nanotubes (CNTs) is a key driver for achieving advances in energy storage, computing, and multifunctional composites, among other applications. Here, we report high‐yield thermal chemical vapor deposition (CVD) synthesis of CNTs catalyzed by reagent‐grade common sodium‐containing compounds, including NaCl, NaHCO3, Na2CO3, and NaOH, found in table salt, baking soda, and detergents, respectively. Coupled with an oxidative dehydrogenation reaction to crack acetylene at reduced temperatures, Na‐based nanoparticles have been observed to catalyze CNT growth at temperatures below 400 °C. Ex situ and in situ transmission electron microscopy (TEM) reveal unique CNT morphologies and growth characteristics, including a vaporizing Na catalyst phenomenon that we leverage to create CNTs without residual catalyst particles for applications that require metal‐free CNTs. Na is shown to synthesize CNTs on numerous substrates, and as the first alkali group metal catalyst demonstrated for CNT growth, holds great promise for expanding the understanding of nanocarbon synthesis.

Engineering the Surface Chemistry and Morphology of Polymeric Carbon Nitrides Towards Greener Heterogeneous Catalysts for Biodiesel Synthesis

“…[36,37] Lower temperatures can be used in the presence of sodium citrate, which has already been reported to facilitate the decomposition and polymerization of urea. [38,39] Differential scanning calorimetry (DSC) analysis (Figure S1, Supporting Information) was used to investigate the behavior of the solids mixture when subjected to heat. The thermograms for the pure compounds urea (X urea = 1.0) and sodium citrate (X urea = 0) evidence a single endothermic event centered at 143.0 and 172.7 °C, respectively, consistent with the melting point of urea and the dehydration of sodium citrate.…”

“…These findings further confirm the TEM and XRD results, suggesting that when more urea is present, more triazine rings can be formed and combined under tris-s-triazine rings to form the PCN structures, which are more organized materials. On the contrary, when the urea concentration decreases, less organized structures are formed [38,39] The presence of functional groups was characterized by Fourier transform infrared (FT-IR) spectroscopy (Figure 1m). Analogous to their precursors (Figure S3, Supporting Information), all catalysts presented bands ascribed to the stretching modes of N-H (3400 to 3300 cm −1 ), O-H (3200 cm −1 ), C=N (1680 cm −1 ), COO − (1580 and 1450 cm −1 ), and C-N (1390 cm −1 ).…”

Low temperature growth of carbon nanotubes – A review

“…In the first reaction, double the quantity of carbon radicals are produced along with water which is associated with the enhanced production of CNTs at lower temperatures. Recently, Li et al introduced the use of common sodium-based compounds such as table salt (NaCl), baking soda (NaHCO 3 ), washing soda (Na 2 CO 3 ), and lye (NaOH), where Na acts as a catalyst in atmospheric thermal CVD growth of CNTs [121]. They utilized the oxidative dehydrogenation reaction between C 2 H 2 and CO 2 to demonstrate CNT growth below 400°C on a range of substrates including Carbon fibers, Alumina fibers, Si wafers and Ti sheets.…”