Graphene and carbon nanotubes have gained significant attention due to their unique properties, such as high surface area, high edge density, and high charge density surfaces. A new hybrid of graphene and carbon nanotubes, G-CNTs, has emerged, possessing a three-dimensional structure, making it an excellent material for gas-sensing applications.

Various methods have been employed to synthesize G-CNTs, such as CVD on copper foil coated with Si NPs, direct synthesis on polycrystalline Cu substrates by thermal CVD method, and catalyst-free plasma-enhanced CVD technique. However, these methods have certain disadvantages, such as the use of conductive substrates and further treatment to make G-CNTs free-standing from the substrate.

The innovation of the current research work is the use of an FCCVD method to synthesize G-CNTs without the use of a substrate. This method provides an advantage in producing a large scale of G-CNTs by controlling the parameters in the experiment. The material synthesized can also be directly used as active sensing materials for gas sensors.

The experimental work involved mixing ethanol, thiophene, and ferrocene and injecting them into FCCVD at 1150°C. The injection rate of the carbon source was varied to study the effect on the formation of G-CNTs and CNTs. The samples were characterized using various techniques, and the results showed that the electrical conductivity response of G-CNTs was higher than that of CNTs. Additionally, the gas-sensing performance of G-CNTs was better than that of CNTs.

In conclusion, the synthesis of G-CNTs using an FCCVD method without the use of a substrate has been reported in this article. The effect of the injection rate parameter of the carbon source on the formation of G-CNTs and CNTs has been studied. The results showed that G-CNTs have better gas-sensing properties and electrical conductivity response than CNTs. This work opens up new possibilities for the selective synthesis of G-CNTs and CNTs via the FCCVD method. G-CNTs can be used in various applications, such as gas sensors, energy storage devices, and electrochemical sensors.

Written by:

Dr. Ismayadi Ismail

ION2, UPM

The original article can be downloaded here:

https://www.hindawi.com/journals/jnm/2019/5717180/

https://doi.org/10.1155/2019/5717180

Date of Input: 10/04/2023 | Updated: 10/04/2023 | roslina_ar