A state‐of‐the‐art review on the application of nanotechnology in biodiesel blends: Exploring the thermo‐chemical interactions, performance improvements, and ecotoxicological aspects

Abstract The growing global emphasis on sustainable energy has intensified interest in biodiesel as a renewable substitute for fossil fuels; however, its higher viscosity, poor atomization, and lower oxidation stability often limit engine performance. Recent advances in nanotechnology have demonstrated that incorporating nanoparticles can overcome these drawbacks by improving the thermochemical behavior of biodiesel blends. Studies have reported that adding 50 to 100 ppm of metal‐oxide or carbon‐based nanoparticles can increase brake thermal efficiency by 4% to 9%, reduce brake‐specific fuel consumption by up to 8%, and lower CO and NO x emissions by 20% to 35%. This review provides a comprehensive synthesis of the mechanisms governing nanoparticle‐fuel interactions, including catalytic oxidation, micro‐explosion phenomena, and enhanced thermal conductivity, which collectively promote complete combustion and improved energy conversion. Furthermore, it analyzes comparative data on nanoparticle type, synthesis route, dosage, and performance outcomes to establish structure–function relationships. Distinct from previous reviews, this article integrates three critical dimensions like thermochemical mechanisms, performance optimization, and ecotoxicological impact, offering a holistic understanding of nanotechnology enabled biodiesel systems. The review also addresses environmental and health concerns related to nanoparticle dispersion, stability, and post‐combustion residues, emphasizing the need for safer nanomaterial design and lifecycle evaluation. By linking mechanistic insights with analytical evidence, this state‐of‐the‐art review aims to guide both research and industrial implementation toward the development of efficient, low‐emission, and environmentally responsible biodiesel formulations aligned with global sustainability goals.