This study focuses on the synthesis of a novel heterogeneous CoO-NiO promoted sulfated ZrO2 (CN/SZ) catalyst and investigating its catalytic efficiency as a transesterification reagent. Catalytic performance has also been compared with two reference catalysts viz., sulfated ZrO2(SZ) and pure ZrO2 (Z). Prepared materials were characterized using X-ray diffraction (XRD) technique, N2- adsorption/desorption study, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDAX), Raman, Fourier Transformed Infrared (FTIR), and X-ray photoelectron (XP) spectroscopy techniques. Surface acidity and basicity were assessed by NH3 and CO2 temperature-programmed desorption (TPD) respectively that established high surface acidity and basicity of CN/SZ nanocatalyst. The reagent has shown supreme catalytic performance as only 0.2 wt% catalyst loading amount has provided 98.8% of biodiesel yield with 3:1 MeOH:Oil molar ratio at 65 degrees C for 2 h. Also, the reusability study has proved the efficacy of CN/SZ nanocatalyst that it can successfully be reused in five consecutive reaction cycles displaying promising results and the reactivated catalyst provided remarkably high biodiesel yield of 96.8%. Further, the mechanistic pathway of the simultaneous catalytic esterification of free fatty acid and transesterification of triglyceride occurring on catalyst surface has also been explored. (C) 2020 Elsevier Ltd. All rights reserved.