Synthesis of carbon nanotubes from biofuel as a carbon source through a diesel engine

Abstract

Carbon nanotube (CNT) was synthesized during combustion in a diesel engine by using biodiesel, fatty-acid methyl ester (FAME), as main fuel. Ethanol which is also known as biomass-derived material was blended with main fuel. These mixed fuel acted as a carbon and heat source. Ferrocene as a catalyst source for CNT growth and molybdenum/sulfur as a promoter were added into mixed fuel. CNTs produced in each experimental condition were assessed mainly by scanning electron microscope and transmission electron microscope whether CNT was really synthesized or not. Gas compositions of an exhaust from an engine were examined by two types of gas chromatograph, thermal conductivity detector for O2, CO, CO2 and flame ionization detector for C1–C3 low molecular hydrocarbons. As a comparative study, experiments using 1-decanol and n-dodecane as main fuel were carried out. The former is an emerging material which has been applied for a diesel engine operation in recent years. The latter has been utilized as surrogate fuel of commercial transport fuel in order to mimic several properties of real fuel. Obtained results indicated that FAME and 1-decanol had a propensity to produce larger CO amount which led to CNT formation than that produced from n-dodecane based fuel even at a low ethanol fraction in fuel. We believe that our outcomes will provide fruitful information that high-valued material like CNT can be produced from biomass-derived materials through a diesel engine which generates electrical power in addition to CNT production.