Fe/Ce bimetallic MOF with synergistic effect for green and efficient low-temperature catalytic upgrading of heavy oil

Heavy oil in-situ catalytic technology faces challenges like complex reservoirs, harsh environments, and high viscosity. Developing efficient in-situ catalysts is a key research focus. This study synthesized a Fe/Ce bimetallic organic framework (Fe/Ce-MOF) that addresses critical issues in heavy oil recovery. Under mild conditions at 140℃ with 0.5 wt% catalyst and 2 wt% hydrogen donor for 24 h, Fe/Ce-MOF achieved a 90.15 % reduction in viscosity and a 16.51 % decrease in asphaltene content. The characterization analysis and simulation results collectively reveal that the bimetallic MOF has a synergistic effect. On the one hand, the Fe 3+ /Fe 2+ redox cycle promotes the cracking of large molecules into smaller ones. On the other hand, the Ce 4+ /Ce 3+ redox cycle facilitates the formation of oxygen vacancies (O v ). Under the combined effect of the dynamic redox cycles of Fe 3+ /Fe 2+ and Ce 4+ /Ce 3+ , the electron transfer efficiency of the catalyst is significantly enhanced, increasing the rate of heavy oil pyrolysis and hydrogenation. The coexistence of Fe and Ce modifies the charge distribution in heavy oil MOF, enhancing Lewis acidity and promoting interaction with heteroatoms. Additionally, the coexistence of mesoporous and macropores in the bimetallic framework not only facilitated mass transfer and fully utilized the catalytic activity of active sites but also effectively resolves the issue of traditional microporous MOFs are prone to being blocked by larger asphaltene molecules, thereby improving their operational stability. This study proposes a novel strategy for the design and development of in-situ catalytic viscosity reduction catalysts for heavy oil, highlighting the high efficiency, excellent stability, and environmental compatibility of bimetallic MOF in low-temperature catalytic pyrolysis, and demonstrating their significant potential for practical applications.