Ultra-low loading of Ni in catalysts supported on mesoporous SiO2 and their performance in hydrodeoxygenation of palmitic acid

Abstract

We synthesized a series of new Ni catalysts supported on mesoporous silica KIT-5. The metal loading on this support was varied (0.9–7.0 wt% NiO). The catalysts were characterized by N₂ physisorption, powder XRD, XRF spectrometry, UV-vis DRS, H₂-TPR, HRTEM and FT-IR with CO. The mesoporous structure is maintained in all the catalytic materials. The increase in the Ni loading resulted in the formation of crystalline phases at the KIT-5 surface. The catalysts were tested in hydrodeoxygenation (HDO) of palmitic acid. The catalytic activity increased with the metal loading, reaching a maximum by using the catalyst with 1.8 wt% NiO. On the other hand, calculation of kinetic parameters indicated the effective utilization of catalytically active Ni particles in the HDO process. Formation of oxygen-free products was higher for the catalyst with higher metal loading in this series. These catalytic materials were compared with a series of Ni catalysts supported on carbon, finding that the Ni/KIT-5 catalysts were much more active in the HDO reaction. These new catalysts supported on the mesoporous silica KIT-5 exhibited high activity with low metal loadings. This feature makes them attractive for their application in the HDO of fatty acids.