Investigation of the WO3/ZrO2 surface acidic properties for the aqueous hydrolysis of cellobiose

A series of WOx/ZrO2 with various tungsten oxide loadings (1–20) wt.% was prepared by co-precipitation. The catalysts were characterized by XRD, BET, XPS, Raman spectroscopy, TPR, ammonia adsorption microcalorimetry and pyridine FT-IR spectroscopy. XRD and Raman results showed that the ZrO2 support is predominantly present in the monoclinic phase when the WO3 loading was less than 5wt.% and predominantly in the tetragonal phase above 10wt.%. No formation of bulk WO3 was detected for the catalysts calcined at 700°C, which is also the case for the highest loaded samples. TPR results revealed that isolated WO3 species are easier to reduce than amorphous WOx. The ammonia adsorption microcalorimetric study evidenced acid sites with adsorption heats in the range 90