Upcycling waste cooking oil into renewable hydrocarbon fuels using CeO₂–La₂O₃–NiO mixed oxide catalysts

CeO₂–La₂O₃–NiO mixed oxide catalysts were engineered using microcrystalline cellulose (MCC) as a green and renewable templating agent to modulate the physicochemical properties of the resulting materials. Comprehensive characterization using thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM)–energy dispersive X-ray spectroscopy (EDX), and N₂ adsorption–desorption confirmed the successful formation of a stable cubic CeO₂ framework, while MCC templating significantly enhanced mesostructural development and surface accessibility. Although the CeO 2 -based oxides (BOCe) 25 wt% microcrystalline cellulose (MCC) catalyst exhibited the highest surface area, the catalyst containing 12.5 wt% MCC was identified as the optimal formulation due to its superior catalytic efficiency rather than textural properties alone. This catalyst possessed a brunauer-emmett-teller (BET) surface area of 36.0 m 2 g -1 and well-defined mesoporosity, which facilitated improved reactant diffusion and oxygen-removal pathways. During catalytic deoxygenation of waste cooking oil at 360°C for 4 h using 1 wt% catalyst loading, the BOCe 12.5 wt% MCC sample achieved complete conversion, delivering a 46% liquid biofuel yield and an exceptional 99% hydrocarbon selectivity. These findings highlight that catalytic selectivity plays a decisive role in optimizing catalyst performance and demonstrate the potential of MCC-templated CeO₂–La₂O₃–NiO mixed oxides as sustainable, high-efficiency catalysts for renewable hydrocarbon fuel production.