Bimetallic NiMo-supported Al2O3@TiO2 core-shell microspheres with high hydrodeoxygenation efficiency toward syringol

In this work, bimetallic NiMo-supported Al2O3@TiO2 core-shell microspheres were developed for the hydrodeoxygenation (HDO) of syringol. First, multi-grams of bimetallic NiMo-supported Al2O3 microspheres containing 20 wt% Ni and 10 wt% Mo were prepared by combining sol-gel and spray pyrolysis (NiMo@Al2O3). Afterwards, a TiO2 anatase shell was decorated onto the surfaces of NiMo@Al2O3 microspheres by hydrolysis of titanium (IV) butoxide with the assistance of an inhibitor. The fabricated NiMo@Al2O3@TiO2 spheres were characterized by XRD, FE-SEM, HR-TEM, N-2 adsorption-desorption, XPS, and H-2-TPR analyses. The results indicate that Ni and Mo species were incorporated well into the gamma-Al2O3 microspheres, which were finely coated by a TiO2 anatase shell layer. HDO experiments showed that the spray pyrolysis-derived bimetallic NiMo-supported catalysts effectively converted syringol with a conversion of similar to 100% at 270 ?degrees C for 3 h, but the hydrocarbon selectivity was still low (similar to 40.3%). By decorating a TiO2 layer shell onto the NiMo@Al2O3 microspheres, enhancing the hydrocarbon selectivity up to similar to 97%, which included methyl-substituted cyclohexanes (similar to 87.7%), cyclohexane (similar to 2%), and 1,1'-bi(cyclohexane) (similar to 7.3%). The findings suggest that coating the NiMo@Al2O3 microspheres containing high catalyst contents with a hydrophobic shell resulted in a synergetic effect that improved the HDO performance. (GRAPHICS)

Automated summary

Bimetallic NiMo-supported Al2O3@TiO2 core-shell microspheres were developed for the hydrodeoxygenation (HDO) of syringol. The NiMo@Al2O3 microspheres containing 20 wt% Ni and 10 wt% Mo were prepared by sol-gel and spray pyrolysis, and a TiO2 anatase shell was decorated onto their surfaces. The decorated spheres showed improved hydrocarbon selectivity in the HDO reaction compared to the undecorated spheres. Coating the NiMo@Al2O3 microspheres with a hydrophobic TiO2 shell improved the HDO performance.