Durable W<sub>20</sub>O<sub>58</sub> Species Catalyzed\nC–C Bond Cleavage in Glucose

WO<sub>3</sub> has been reported to be active in selectively\ncleaving\nthe C–C bonds of glucose. A frequently occurred problem with\nthis catalytic reaction is low activity and poor cycling performance\ncaused by the in situ-generated hydro tungsten bronze (e.g., H<sub>0.23</sub>WO<sub>3</sub>) which seriously leaches in hot water. In\nthis work, we prepared intrinsically oxygen-deficient W<sub>20</sub>O<sub>58</sub> by the reduction of WO<sub>3</sub> in H<sub>2</sub>. It had a higher robustness during the reaction of glucose that\nno phase change was observed from XRD patterns and the yields of ethylene\nglycol and propylene glycol remained stable over five recycling runs.\nIn comparison to the conventional WO<sub>3</sub> catalyst which lost\n27% after five cycles, the loss of W<sub>20</sub>O<sub>58</sub> after\nthe same treatment was only 7%. The high-temperature hydrogen treatment\nturned WO<sub>3</sub> into W<sub>20</sub>O<sub>58</sub>. Lattice distortion\nof tungsten–oxygen octahedra caused the formation of abundant\noxygen vacancies in W<sub>20</sub>O<sub>58</sub>, which largely precluded\nthe adsorption of hydrogen and the formation of hydro tungsten bronze.\nBesides higher stability, W<sub>20</sub>O<sub>58</sub> also showed\nhigher catalytic activity to cleave C–C bonds in glucose than\nH<sub>0.23</sub>WO<sub>3</sub>. In situ IR, solid-state UV, EPR, and\nRaman characterizations demonstrated that substantial oxygen vacancies\non the surface of W<sub>20</sub>O<sub>58</sub> favored the binding\nwith C=O group in glucose and promoted the cleavage of the C–C\nbond at the beta-position to the C=O group.