<p>Green synthesis is an important route in the preparation of bare metals and metal oxides that provides cost-effective, eco-friendly, and highly efficient catalysts for catalyzing various reactions. In this paper we report, for the first time, the green synthesis of Co₃O₄ employing jasmine flower extract as a green precursor for the application as catalyst during NaBH₄ hydrolysis. Moreover, the role of calcination temperature (300–900&#xa0;°C) on stability, morphology, texture, and catalytic performance of the formed Co₃O₄ have been addressed too. Co₃O₄ was found to be the major formed phase together with trace quantities of graphitic carbon over the 300–700&#xa0;°C range. Pushing the calcination temperature to 900&#xa0;°C was associated with a thermal reduction of Co₃O₄ to CoO and the elimination of the graphitic carbon. The highest activity was obtained using the 700&#xa0;°C calcined catalyst (4449 ml g^− 1 min^− 1 at 45&#xa0;°C).</p> Graphical Abstract <p></p>