Role of Support Oxygen Vacancies in the Gas Phase Hydrogenation of Furfural over Gold.

ABSTRACT

We have examined the role of support oxygen vacancies in the gas phase hydrogenation of furfural over Au/TiO and Au/CeO prepared by deposition-precipitation. Both catalysts exhibited a similar Au particle size distribution (1-6 nm) and mean (2.8-3.2 nm). Excess H consumption during TPR is indicative of partial support reduction, which was confirmed by O titration. Gold on CeO with a higher redox potential exhibited a greater oxygen vacancy density. A lower furfural turnover frequency () was recorded over Au/CeO than Au/TiO and is linked to suppressed H chemisorption capacity and strong -C=O interaction at oxygen vacancies that inhibited activity. Gold on non-reducible AlO as benchmark exhibited greater H uptake and delivered the highest furfural . Full selectivity to the target furfuryl alcohol was achieved over Au/TiO and Au/AlO at 413 K and over Au/CeO at 473 K with hydrogenolysis to 2-methylfuran at higher reaction temperature (523 K). A surface reaction mechanism is proposed to account for the activity/selectivity response.