Insights into influence of CeO2 crystal structure effects on hydrothermal hydrogenation for palmitic acid over Ni/CeO2 catalysts

Abstract

In recent years, upgrading renewable bio–oil to hydrocarbon fuels has received increasing attention. It is crucial to develop a catalyst with high activity, low cost, and high hydrothermal stability for bio–oil upgrading. In this work, the non-noble metal Ni/CeO2 is proved to be a potential catalyst for hydrothermal hydrogenation of palmitic acid (model compound of microalgae based bio–oil). The effect of the crystal structure of the support on the hydrothermal hydrogenation activity of palmitic acid is investigated for the first time. The research results indicate that the catalytic activity of catalysts with different support crystal structures is in the following order: Ni/CeO2–r (nanorods) > Ni/CeO2–c (nanocubes) > Ni/CeO2–p (nanoparticles). The excellent activity of Ni/CeO2–r is attributed to its larger specific surface area, higher defect and oxygen vacancy concentration, and the formation of more Ni0 due to strong metal − support interaction (SMSI). After optimization of conditions at 300 °C, 98.9 % conversion and 92.4 % alkanes yield are obtained over the Ni/CeO2–r. In addition, the coating structure formed by the SMSI provides good hydrothermal stability for the catalyst.