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Previous studies have shown that fats, oils, and greases (FOG) can be deoxygenated to fuel-like hydrocarbons over inexpensive alumina-supported Ni catalysts promoted with Cu or Fe to afford excellent yields of renewable diesel (RD). In this study, supports other than alumina—namely, SiO2-Al2O3, Ce0.8Pr0.2O2, and ZrO2—were investigated to develop catalysts showing improved RD yields and resistance to coke-induced deactivation relative to Al2O3-supported catalysts. Results showed that catalysts supported on Ce0.8Pr0.2O2 and ZrO2 outperformed SiO2-Al2O3-supported formulations, with 20%Ni-5%Fe/ZrO2 affording a quantitative yield of diesel-like hydrocarbons. Notably, the abundance of weak acid sites varied considerably across the different supports, and a moderate concentration of these sites corresponded with the best results. Additionally, temperature-programmed reduction measurements revealed that Ni reduction is greatly dependent on both the identity of the promoter and catalyst support, which can also be invoked to explain catalyst performance since metallic Ni is identified as the likely active site for the deoxygenation reaction. It was also observed that Ce0.8Pr0.2O2 provides high oxygen storage capacity and oxygen mobility/accessibility, which also improves catalyst activity.