Catalytic Activity of Bulk WO3 for the Reforming of Hexanes and Hexenes

In Situ XAS and XRD Studies on the Structural Evolution of Ammonium Paratungstate During Thermal Decomposition

“…helium, propene, and hydrogen) to WO 2 or tungsten metal is detected during the decomposition of APT under hydrogen only. [17,[26][27][28] Apparently, propene is not capable of further reducing WO 3 in the temperature range employed. This difference between the reducing powers of hydrogen and propene has already been observed for the reduction of MoO 3 under propene and hydrogen.…”

WO3 microcrystallites: One of the crucial factors controlling the isomerization activity of Pt/WO3–ZrO2

“…At a higher temperature of 720 • C, a not well resolved peak was observed at in the TPR profiles of PWZr-150 and PWZr-200 samples, while it was not visible for PWZr-110. A larger reduction peak at a higher temperature above 800 • C was observed for all the samples, which was attributed to the reduction of WO x species strongly bond to the zirconia support [20]. The different reduction behaviors of the samples may be indicative of different states of tungsten oxide.…”

Temperature-programmed and X-ray diffractometry studies of hydrogen-reduction course and products of WO3 powder: Influence of reduction parameters

“…Upon further reduction, oxygen vacancies are progressively formed and, hence, W 4+ ions are generated and paired with the metallic state (W o ) to show an apparent oxidation state of "2+". These reductive modifications of the surface chemistry of WO 3 particles have been, a few years later, allocated the responsibility of alkene and alkane reforming catalytic activity shown to develop with time of thermal treatment of the oxide particles in H 2 atmosphere [14][15][16][17]. Precisely speaking, it is the pertinent population of density of states in the 5d and 6s orbitals [1] that develops the metallic character required for the initial hydrogenation/dehydrogenation of the hydrocarbon; whereas, the generated OH-groups provide the necessary Brönsted acidity for the subsequent skeletal rearrangement (isomerization) [18].…”