Effect of tungsten surface density of WO3–ZrO2 on its catalytic performance in hydrogenolysis of cellulose to ethylene glycol

Abstract

One-pot hydrogenolysis of cellulose to ethylene glycol (EG) was carried out on WO₃-based catalysts combined with Ru/C. To probe the active catalytic site for breaking the C–C bond of cellulose, a series of WO₃–ZrO₂ (WZr) catalysts were synthesized and systematically characterized with XRD, Raman, UV-Vis, H₂-TPR, DRIFS and XPS techniques and N₂ physisorption experiment. It was found that the WO₃ crystallites became more easily reduced to W⁵⁺–OH species with increasing crystallite size or tungsten surface density of the WZr catalyst owing to the decrease of their absorption edge energy (AEE) originating from weakening their interaction with ZrO₂ support. This, as a result, gave higher EG yield at higher tungsten surface density. The structure–activity relationship of the WZr catalyst reveals that the active catalytic site for cleaving the C₂–C₃ bond of the glucose molecule is the W⁵⁺–OH species.