An experimental and ReaxFF-MD simulation study on effects of ferrocene on combustion characteristics of biodiesel-diesel blends

Biodiesel has high viscosity, leading to incomplete combustion when blended with diesel. Adding combustion catalysts has emerged as an effective method to mitigate these issues. Ferrocene possesses high oil solubility, making it suitable as a combustion catalyst, yet its influential mechanism on the combustion characteristics of biodiesel-diesel blends remains unclear. In this study, TG-FTIR-MS experiments and ReaxFF-MD simulations were conducted to systematically elucidate the impact of ferrocene on the pyrolysis, oxidation, pollutant emission characteristics of Jatropha biodiesel-diesel blends (BD50), as well as the dominant reaction mechanism. The findings indicate that ferrocene reduces the activation energy ($E_a$) of the pyrolysis and oxidation in the BD50 by 5.85 kJ/mol and 6.30 kJ/mol. Ferrocene promotes the hydrogen abstraction reaction of fuels with H in pyrolysis to produce more H₂. Ferrocene boosts the oxidation process of BD50 by enhancing the hydrogen abstraction reactions of fuels with O₂, ·OH and ·OOH. Ferrocene results in a 24.9 % reduction in CO emissions, a 21.9 % increase in NO_x emissions, and a 19.53 % reduction in soot particle size. The findings provide theoretical and practical guidance for the development of clean and efficient combustion for biodiesel-diesel.