Karisma Pradina Putri, Muhammad Falila Izzuddin Haqq, Muhammad Naufal Alhilmy, Moh. Nadhif Mauluddin, A. Ghanaim Fasya, Susi Nurul Khalifah, Saidun Fiddaroini
Sustainable production of green diesel from waste feedstocks represents a promising strategy to address sustainability challenges in the global energy transition. This study evaluates the catalytic deoxygenation of waste corn oil over γ-Al₂O₃-supported monometallic and bimetallic catalysts under hydrogen-free conditions. Ni/γ-Al₂O₃ (10 wt% Ni), Mo/γ-Al₂O₃ (10 wt% Mo), and Ni–Mo/γ-Al₂O₃ (5 wt% Ni, 5 wt% Mo) catalysts were synthesized via wet impregnation followed by sonication, drying, and calcination. The catalysts were characterized using XRD, ATR-FTIR, N₂ adsorption–desorption, SEM–EDX, and ICP-OES. Deoxygenation reactions were conducted in a semi-batch reactor at 360 °C for 4 h under an inert N₂ atmosphere without external hydrogen. The waste corn oil feedstock, rich in C18 fatty acids, is suitable for producing diesel-range hydrocarbons. Among the tested catalysts, Ni–Mo/γ-Al₂O₃ achieved the highest liquid yield of 39.66%, representing a 22.2% increase relative to γ-Al₂O₃. The hydrocarbon content reached 91% (35.8% improvement), while diesel selectivity increased to 68% (41.7% enhancement). Paraffin selectivity also increased to 62%, representing a 3.3% improvement compared with γ-Al₂O₃. Catalyst reproducibility, reusability, and stability tests demonstrated that Ni–Mo/γ-Al₂O₃ retained stable catalytic performance over repeated reaction cycles, while thermogravimetric analysis (TGA) of the spent catalyst revealed carbon deposition as the main cause of catalyst deactivation. The superior performance of Ni–Mo/γ-Al₂O₃ originates from the synergistic interaction between NiO and MoO₃ species with complementary catalytic roles. NiO sites promote C–O bond cleavage through decarboxylation and decarbonylation pathways, whereas MoO₃ domains stabilize oxygenated intermediates and regulate secondary reactions such as cracking. This cooperative interaction enhances oxygen removal and favors the formation of diesel-range hydrocarbons under hydrogen-free conditions, highlighting the potential of Ni–Mo/γ-Al₂O₃ for sustainable green diesel production. © 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/
Chemistry Study Program, Science and Technology Faculty, Universitas Islam Negeri Maulana Malik Ibrahim, Malang, 65144, Indonesia; Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Chemistry Department, Faculty of Mathematic and Natural Sciences, Brawijaya University, Malang, 65144, Indonesia
