Promotion Effects of Copper and Lanthanum Oxides on Nickel/Gamma-Alumina Catalyst in the Hydrotreating of Crude 2-Ethylhexanol

摘要

Nickel/gamma-alumina (Ni/γ-Al2O3) catalysts promoted with Cu and La were prepared by the impregnation method and characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). XRD and HRTEM indicated that the addition of La and Cu was helpful to decrease the size of active particles and increase the dispersion of Ni species. TPR showed that Cu can effectively decrease the reduction temperatures of its own and Ni oxides, whereas La can change the proportion of various Ni species and increase the content of easily reducible Ni species. XPS and UV-vis DRS indicated that electron shift occurred on the Ni-based sample modified by Cu and enhanced remarkably by adding La. These findings suggest that Cu and La species induce both structural and electronic promotion effects, resulting in smaller particle size and weaker interaction between active components and the support, higher dispersions, and reducibility of active phases, ultimately enhancing the crude 2-ethylhexanol hydrotreating catalytic performance.