Polymethyl Methacrylate assisted mesoporous TiO₂ supported Ni–Co alloy catalysts for the in situ hydrodeoxygenation of methyl palmitate

Herein, the Ni–Co alloy supported on TiO₂ catalysts were prepared by sol–gel method assisted with Polymethyl Methacrylate (PMMA) template, and they were tested for in situ aqueous phase hydrodeoxygenation (HDO) of methyl palmitate to hydrocarbons using methanol as hydrogen donor. It has been found that the introduction of PMMA decreases the Ni–Co alloy particles size, reduces the metal-support interactions (SMSI), constructs the mesopores and enlarges the mesopore size. Also, the Ni–Co alloy particles can be partially embedded in TiO₂, beneficial to the catalyst stability since the sintering and leaching of the Ni–Co alloy particles can be suppressed under hydrothermal condition. In the in situ HDO of methyl palmitate, the main deoxygenation pathway is decarboxylation/decarbonylation on the Ni–Co alloy catalysts. The catalysts prepared with PMMA exhibits higher activity than that without PMMA, giving the pentadecane yield of 86.2% at 310 °C. This is ascribed to their more exposed active sites and wider mesopores. Moreover, the catalyst is not obviously deactivated during five reactions.