<p>The influence of nanoadditives on biofuels alongside oxygenated additives is still unexplored in terms of fuel spray properties and rarely explored in context of performance and emissions. This study aims to produce ecofriendly renewable nanofuels by addressing this research gap. Molybdenum disulfide (MoS₂) nanoparticles and acetone–butanol–ethanol (ABE) were used as a fuel additive to castor biodiesel to produce novel fuel blends. These fuels were investigated in terms of their macroscopic spray behavior, engine performance, and emission characteristics. Spray analysis revealed a longer fuel penetration length (0.9–2.5%), a wider spray cone angle (3–4.9%), and a higher spray-projected area (3.5–5.5%) with the addition of MoS₂ nanoadditives. Nanofuels showed reduced FPL − (2.13% and 1.67%), wider SCA + (4.8% and 12.2%), and higher SPA + (4.5% and 5.8%) in contrast to the fuels without nanoadditives. Performance evaluation showed reduced brake-specific fuel consumption by 3.1–4.1% and increased brake thermal efficiency by 3.9–4.2% with the addition of MoS₂ nanoparticles to castor biodiesel at the peak load. Adding MoS₂ alongside ABE to castor biodiesel caused the maximum reduction in CO, CO₂, and NO_x emissions, which were 38.8%, 36.3%, and 43.09% lower than diesel emissions.</p> Graphical abstract <p></p>