AbstractIn this article, we investigate the effects of Arrhenius activation energy with binary chemical reaction and convective boundary condition on natural convective flow over vertical frustum of a cone in a Buongiorno nanofluid under the presence of thermal radiation. The zero nanoparticle flux condition is used at the surface of frustum of a cone rather than the uniform wall condition to execute physically applicable results. For this complex flow model, a suitable non-similarity transformations are used initially and then Bivariate pseudo-spectral local linearisation method is used to solve the non-similar, coupled partial differential equations. Further, the convergence test and error analysis are conducted to verify the accuracy of numerical method. The effects of flow influenced parameters on the non-dimensional velocity, temperature, nanoparticle volume fraction and regular concentration profiles as well as on the skin friction, heat transfer rate, nanoparticle and regular mass transfer rates are analyzed.