Enhancing Cerium Oxide Nanoparticle Stability in Diesel–Biodiesel Blends via Alumina Nanoparticle Amalgamation

To reduce the environmental impacts and emissions while maintaining energy efficiency, it is a common practice to blend diesel with biodiesel. However, it can be a challenging task due to the dissimilar specifications of these fuels and the resulting blend may not show the desirable combustion properties. These shortcomings can be overcome by adding nanoparticles which significantly enhance the thermophysical properties and combustion characteristics of fuel blends. However, a critical challenge is preserving the stability of these nanoparticles within fuel blends, as they have a high tendency to agglomerate. This study addresses the issue of the poor stability of cerium oxide (ceria) nanoparticles in a fuel blend composed of 80 v% diesel and 20 v% waste cooking oil (WCO)-derived biodiesel. To this end, a novel approach was adopted to amalgamate ceria with alumina nanoparticles using a solvent-based method. The resulting cerium-alumina nanocomposite demonstrated 44% greater stability within a month than the fuel blend containing ceria nanoparticles alone. In comparison to pure biodiesel, the fuel blend incorporating the nanocomposite exhibited a 6 MJ/kg increase in heating value, a 1.5 mm 2 /s reduction in kinematic viscosity, a 100 °C decrease in flash point, an 8 °C decrease in cloud point, and a13 °C reduction in pour point. Graphical Abstract