Alignment and structural control of nitrogen-doped carbon nanotubes by utilizing precursor concentration effect

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Carbon nanotubes (CNTs) exhibit unique properties, driving research into their controlled synthesis.
• Nitrogen-doped CNTs (NCNTs) offer enhanced electronic and chemical characteristics.
• Controlling NCNT morphology, such as alignment and tip structure, is crucial for advanced applications.

Purpose of the Study:

• To investigate the effect of precursor concentration on nitrogen-doped carbon nanotube (NCNT) properties.
• To achieve controlled alignment, diameter, and open-tip formation in NCNTs.
• To elucidate the growth mechanism linking precursor composition to NCNT morphology.

Main Methods:

• Ultrasonic spray pyrolysis for NCNT synthesis.
• Systematic variation of xylene/cyclohexylamine precursor ratio.
• Characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS).

Main Results:

• NCNT alignment and diameter increased with cyclohexylamine content up to 35%.
• A significant number of open-ended NCNTs with internal graphite layers were formed at optimal precursor ratios.
• Higher cyclohexylamine concentrations led to reduced alignment and smaller diameters.

Conclusions:

• Precursor composition in ultrasonic spray pyrolysis is a key factor for controlling NCNT alignment, diameter, and tip structure.
• The study demonstrates a method for fabricating tailored NCNTs with desirable features.
• A growth mechanism is proposed to explain the observed structure-property relationships in NCNTs.