BACKGROUND: Oils derived from plants, animal fats, and algae contain both saturated and unsaturated fatty acids. These fatty acids can be converted into liquid fuels and chemicals in the presence of active solid catalysts. RESULTS: Nickel-based catalysts were supported on mordenite via ion exchange synthesis and evaluated for the deoxygenation of stearic acid to diesel fuels. By tuning the synthesis pH, loadings of over 20 wt% Ni were obtained. Catalysts synthesized at pH 8.5 displayed the highest Ni loading and the highest activity for the decarboxylation/decarbonylation of stearic acid under inert nitrogen gas atmospheres, yielding 47% heptadecane. Characterization included scanning transmission electron microscopy-energy-dispersive spectroscopy (STEM-EDS), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES), N-2 physisorption and thermogravimetric analysis (TGA), providing new insights into the recyclability of the catalyst. The observed loss of catalytic activity upon recycling was attributed to the agglomeration of Ni nanoparticles and the accumulation of carbonaceous coke. CONCLUSION: This work demonstrates that Ni-based catalysts supported on mordenite zeolite can effectively convert stearic acid into heptadecane. Yields to heptadecane were as high as 47%. Mechanistically, the reaction proceeds by decarboxylation and decarbonylation pathways. (C) 2019 Society of Chemical Industry