Nanofluid is treated as a smart fluid that is useful for heat and mass transfer enhancement, which is paramount in several electronics, biomedical, transportation as well as industrial applications. In view of this, in the current analysis we scrutinize the flow of nanofluid over a curved stretching sheet. The noted novelty of this work is to discuss the heat and mass transfer in nanofluid flow along with the activation energy. Further, CuO with water-based nanofluid is considered in the modelling. The viscosity and effective thermal conductivity of fluid flow suspended by nanoparticles are scrutinized by Koo–Kleinstreuer–Li (KKL) model. By employing suitable similarity transformations, the governing equations of momentum, thermal and concentration of nanoparticle are converted into ordinary differential equations and then they are solved with Runge–Kutta-Fehlberg-45 (RKF-45) process along with shooting method. The impact of pertinent non-dimensional parameters is attained and illustrated with the help of graphs. The results reveal that, the heightening of Biot number and curvature parameter heightens the thermal gradient. The mass transfer decreases as the Schmidt number and chemical reaction rate parameter increases. The upsurge in activation energy parameter declines the mass transfer.