Enhanced hydrodeoxygenation of methyl laurate over NiRe alloy supported TiO2 catalyst via a phase engineering strategy

The catalytic activity of metal nanoparticles is strongly correlated with reducible support, but scant knowledge exists on the effect of the crystal phase of the reducible support on the catalytic activity. Herein, we investigated the conversion of methyl laurate over NiRe/TiO2 catalysts by modulating hydrochloric acid concentration to control crystal phase structures. The optimal NiRe/Mix-TiO2 exhibited excellent catalytic performance with 100 % yield of alkanes (240 °C, 3.5 MPa, 5 h) and 76.06 % yield of fatty alcohol (180 °C, 2.5 MPa, 18 h). The effect of different crystal phases on the catalytic performance was unveiled via experiments, characterization and calculations. The results indicated that NiRe/A-TiO2 with more alloyed NiRe nanoparticles contributed to hydrogen activation and dissociation, and enhanced hydrogen spillover (62 μmol/g). The NiRe/R-TiO2 with oxygen-rich vacancies (19.6 % OV) contributed to the adsorption of methyl laurate. The synergistically enhanced NiRe/Mix-TiO2 exhibited the most excellent catalytic performance, which was attributed to the highest oxygen vacancy concentration (39.1 % OV) and moderate hydrogen spillover (42 μmol/g). This work provided a feasible method to improve the alkanes and alcohol yield for mild-condition hydro-conversion of methyl laurate by crystal phase regulation engineering.