Controlling Hydrodeoxygenation of Stearic Acid to n-Heptadecane and n-Octadecane by Adjusting the Chemical Properties of Ni/SiO₂–ZrO₂ Catalyst

A series of SiO₂–ZrO₂ mixed oxides with varying SiO₂ concentrations were hydrothermally synthesized and used as support for Ni in the hydrodeoxygenation of stearic acid. ZrO₂ provides a relatively low surface area and only Lewis acid sites, and Ni supported on ZrO₂ produces n-heptadecane from stearic acid through hydrogenation and decarbonylation. The SiO₂–ZrO₂ mixed oxides have a higher specific surface area than ZrO₂ as well as an unprecedented spherical and nanolayered morphology. Brønsted acid sites were created by the incorporation of SiO₂ into ZrO₂, promoting the hydrodeoxygenation activity of Ni and specifically opening a new reaction route to n-octadecane through the dehydration of 1-octadecanol intermediate into 1-octadecene with subsequent hydrogenation.