In-Situ Hydrodeoxygenation of Methyl Palmitate on a TiO₂–ZrO₂ Supported Ni₃Sn₂ Intermetallic Compound with Methanol as a Hydrogen Donor in the Aqueous Phase

Ni₃Sn₂/TiO₂, Ni₃Sn₂/TiO₂–ZrO₂(x:y) (x:y indicates the Ti/Zr atomic ratio), and Ni₃Sn₂/ZrO₂ catalysts were prepared by the sol–gel method and tested for in situ hydrodeoxygenation of methyl palmitate with methanol as the hydrogen donor. The Ni₃Sn₂ intermetallic compound (IMC) is formed in all of the catalysts. The Ti–O–Zr bonds are generated in the TiO₂–ZrO₂ mixed oxide, leading to more Lewis acid sites on Ni₃Sn₂/TiO₂–ZrO₂(x:y) than those on Ni₃Sn₂/TiO₂ and Ni₃Sn₂/ZrO₂, and Lewis acid sites may contribute to the C–O bond cleavage. Especially, among the as-prepared catalysts, Ni₃Sn₂/TiO₂–ZrO₂(2:1) has the largest specific surface area and the smallest Ni₃Sn₂ particles, subsequently giving rise to the highest activity for in situ hydrodeoxygenation. The decarbonylation pathway dominates on all of the supported Ni₃Sn₂ IMC catalysts. At 330 °C, the yield of n-pentadecane on Ni₃Sn₂/TiO₂–ZrO₂(2:1) reaches 91.2%. Ni₃Sn₂/TiO₂–ZrO₂(2:1) shows slight deactivation after reaction for five times, mainly due to carbon deposition and the slight sintering of Ni₃Sn₂ IMC particles.