Carbon Nanotube Synthesis Using Coal Pyrolysis
Kapil Moothi, Geoffrey S Simate, Rosemary Falcon
1Center for Nanotechnology, NASA Ames Research Center , Moffett Field, California 94035, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 12, 2015
Summary
This study explores producing carbon nanotubes (CNTs) from coal pyrolysis gases. Optimal production occurs between 400-500°C, using methane and carbon monoxide as primary feedstocks for cost-effective CNT synthesis.
Area of Science:
- Materials Science
- Chemical Engineering
- Nanotechnology
Background:
- Carbon nanotubes (CNTs) are valuable nanomaterials with diverse applications.
- Traditional CNT production often relies on expensive, high-purity carbon sources.
- Coal pyrolysis offers a potentially cheaper alternative feedstock for CNT synthesis.
Purpose of the Study:
- To investigate the feasibility of producing CNTs from coal pyrolysis gases.
- To develop a predictive model for gas product volumes during coal pyrolysis.
- To establish a kinetic rate law for CNT formation from these gases.
Main Methods:
- Utilizing output gases from coal pyrolysis in a chemical vapor deposition (CVD) reactor.
- Employing Gibbs minimization modeling to predict gas compositions.
- Deriving a kinetic rate law based on experimental observations.
Main Results:
- Coal-derived gases yielded CNTs comparable to commercial sources.
- Methane and carbon monoxide were identified as key carbon sources for CNT synthesis.
- Optimal pyrolysis temperature for useful gas production was found to be 400-500 °C.
Conclusions:
- Coal pyrolysis is a viable and cost-effective method for CNT precursor gas production.
- The derived kinetic rate law, d[CNT]/dt = K([CO][CH4])(1/2), accurately describes CNT formation.
- Temperature control is crucial for maximizing the yield of useful gases in coal pyrolysis for CNT synthesis.
