This study aims to improve gold-based catalyst effectiveness in n-octanol oxidation by adjusting the structural and electronic properties of gold through incorporation of additives to support. Au/La/TiO2, Au/Ce/TiO2, and Au/TiO2 catalysts, prepared by deposition-precipitation with urea, were tested in the base-free oxidation of octanol under mild conditions in liquid phase. The influence of additives on structural properties of the catalyst and the active phase, and on the electronic and redox properties of the active gold species was studied by TEM, SR-XRD, EXAFS, FTIR of adsorbed CO, and XPS. Support modifiers affected gold particle size distribution, but no direct dependence of the catalyst activity on Au NPs average size was observed. The activity of as-prepared catalysts was limited, and even lower in the presence of modifiers at that stage. Reductive pretreatment boosted the activity of every catalyst, and support modification with La and Ce increased four- and two-fold, respectively, the activity of Au/TiO2 under the same reaction conditions. The nature of modifiers also affected the product distribution where the outstanding performance of Au/La/TiO2 gives rise to the highest ester selectivity at isoconversion with no acid formation. Overall, the studied catalysts, and especially Au/Ce/TiO2, and Au/La/TiO2, hold promise for n-octanol oxidation under mild conditions.
ASJC Scopus subject areas
- Process Chemistry and Technology
- Physical and Theoretical Chemistry