Promoted Hexagonal Tungsten Bronzes as Selective Catalysts in the Aerobic Transformation of Alcohols: Glycerol and Methanol

摘要

M-containing tungsten oxides bronzes (M = Ti, Nb or V) with hexagonal tungsten bronze (HTB) structure have been investigated as catalysts for the aerobic transformation of glycerol and methanol. The catalysts were prepared hydrothermally and characterized by several physico chemical techniques, i.e. N-2-adsorption, XRD, Raman spectroscopy and temperature programmed desorption of ammonia. Interesting variations in the thermal stability of the HTB-framework were observed according to the element introduced into the oxide structure. In addition, the incorporation of Ti and Nb modified the acid features of the hexagonal tungsten oxides, whereas V introduced new redox sites. The catalytic results for the aerobic transformation of glycerol and methanol in terms of conversion and nature of reaction products are discussed on the basis of the physicochemical characteristics of catalysts.