Enhanced oxygen removal ability of sulfur-doped Ru/TiO2 catalyst in low-temperature hydrodeoxygenation of guaiacol

Abstract

Hydrodeoxygenation of bio-oil to obtain oxygen-free hydrocarbon at low-temperature remains a substantial challenge to produce economically feasible biomass-derived fuel. Among the various Ru-loaded catalysts, Ru/ DT-51, a sulfate-containing anatase TiO2, showed prominent oxygen removal attributed to the sulfur content of the catalysts. The introduction of sulfur on Ru/TiO2 resulted in lower conversion of guaiacol, although the degree of oxygen removal obtained at 100% conversion was significantly enhanced, with 50% even at mild reaction temperature of 100 degrees C. The introduction of sulfur modified the distribution of exposed Ru species by selectively covering Ru in the form of sulfide, which was confirmed through X-ray photoelectron spectroscopy (XPS), CO chemisorption, CO diffuse reflectance infrared Fourier transform (CO-DRIFT), and temperatureprogrammed-desorption of ammonia coupled with a mass detector (NH3-TPD-MS). By introducing sulfur to Ru/TiO2, the product selectivity in guaiacol HDO was regulated to enhance the oxygen removal even at a low temperature of 100 degrees C.