Exfoliation of MoS2 nanosheets via reaction–diffusion framework for enhanced boundary lubrication performance in crude Jatropha oil

Purpose This study aims to evaluate the tribological performance of exfoliated MoS2 nanosheets synthesized via a reaction–diffusion (RD) method and dispersed in crude Jatropha oil, with a focus on reducing friction and wear under boundary lubrication conditions. Design/methodology/approach MoS2 nanosheets with controlled particle sizes (20–30 nm, 50–60 nm and 80–90 nm) were synthesized using a diffusion-driven RD protocol and subsequently isolated from an agarose matrix. Nine MoS2–Jatropha oil dispersions were prepared at concentrations of 0.25, 0.50 and 1% (w/v). The structural and morphological features of MoS2 were characterized using SEM, FESEM, XRD, Raman and UV–Vis analyses. Tribological testing was performed on a four-ball tribometer following ASTM D4172 to determine the coefficient of friction, frictional torque and wear scar diameter. Findings The incorporation of RD-synthesized MoS2 nanosheets significantly enhanced the lubrication performance of crude Jatropha oil. All MoS2 dispersions displayed reduced friction, torque and wear compared to base oil. Wear resistance improved consistently with increasing particle size and concentration, with the best protection (0.331 mm wear scar) achieved at 1% MoS2 containing 80–90 nm sheets. Stable colloidal dispersions, as confirmed by the Tyndall effect, further supported the nanosheet stability within the lubricant. Practical implications The synergistic combination of RD-exfoliated MoS2 nanosheets and crude Jatropha oil presents a promising approach for formulating high-performance, biodegradable lubricants suitable for industrial applications operating under boundary lubrication conditions. Originality/value The study provides new insights into particle-size-dependent lubrication mechanisms of 2D materials in natural oils, offering a sustainable alternative to petroleum-derived lubricants. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2025-0545/