Durable W₂₀O₅₈ Species Catalyzed C-C Bond Cleavage in Glucose

WO₃ has been reported to be active in selectively cleaving the C-C bonds of glucose. A frequently occurred problem with this catalytic reaction is low activity and poor cycling performance caused by the in situ-generated hydro tungsten bronze (e.g., H_0.23WO₃) which seriously leaches in hot water. In this work, we prepared intrinsically oxygen-deficient W₂₀O₅₈ by the reduction of WO₃ in H₂. It had a higher robustness during the reaction of glucose that no phase change was observed from XRD patterns and the yields of ethylene glycol and propylene glycol remained stable over five recycling runs. In comparison to the conventional WO₃ catalyst which lost 27% after five cycles, the loss of W₂₀O₅₈ after the same treatment was only 7%. The high-temperature hydrogen treatment turned WO₃ into W₂₀O₅₈. Lattice distortion of tungsten-oxygen octahedra caused the formation of abundant oxygen vacancies in W₂₀O₅₈, which largely precluded the adsorption of hydrogen and the formation of hydro tungsten bronze. Besides higher stability, W₂₀O₅₈ also showed higher catalytic activity to cleave C-C bonds in glucose than H_0.23WO₃. In situ IR, solid-state UV, EPR, and Raman characterizations demonstrated that substantial oxygen vacancies on the surface of W₂₀O₅₈ favored the binding with C=O group in glucose and promoted the cleavage of the C-C bond at the beta-position to the C=O group.