<p>This study investigates the novel synthesis of Aluminium Oxide nanoparticles using <i>Oxalis corniculata</i> leaves extract as a biogenic and eco-friendly approach. Absorption peak (lambda max) at 220&#xa0;nm was obtained through UV–Vis spectrum. Scanning Electron Microscopy studies show the hexagonal rod-like morphology with an average size of 10&#xa0;nm. The catalytic application of Aluminium Oxide nanoparticles in the reduction of Methylene Blue dye and the pyrolysis of corncob was also evaluated. The kinetic methods showed lower activation energy values for corncob with an aluminium oxide nanoparticles catalyst compared to pure corncob, indicating a facile degradation of biomass. The thermodynamic analysis using the Kissinger-Akahira-Sunose model for corncob pyrolysis in the presence of catalyst showed 98.36&#xa0;kJ mol⁻¹, -34.89&#xa0;Jmol⁻¹ K⁻¹, and 117.7&#xa0;kJ mol⁻¹ values of Enthalpy, Entropy, and Gibbs free energy, respectively. The calorific value of obtained bio-oil with Aluminium Oxide nanoparticles was found to be 38.2 ± 0.01&#xa0;MJ kg⁻¹, which was nearly equal to standard values of gasoline and diesel. The Aluminium Oxide nanoparticles also demonstrated complete mineralization of methylene blue dye in 35&#xa0;min.</p> Graphical Abstract <p></p>