On the reduction of tungsten blue oxide in a stream of hydrogen

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

“…Whereas, tungstenrich oxides (W n O, where n ≥ 2) with obvious metallic character, have been encountered and reported previously [1]. Namely, W 3 O has been observed repeatedly in the reduction course not only of WO 2 , but also of WO 2.9 , and denoted ␤-W o [1,12]. Fig.…”

“…Hence, the reduction process has been the focus of numerous research investigations including extensive thermodynamic [1,2], kinetic [3][4][5], morphological [1,6,7], and characterization [1,[8][9][10][11][12] studies. These studies employed a wide range of bulk and surface, isothermal and nonisothermal, thermoanalytical (TGR, TPR, TPO and TPD), microscopic (TEM and SEM) and spectroscopic (XRD, IR, Raman, XPS, etc.)…”

“…Reportedly [1][2][3][4][5][6][7][8][9][10][11][12], oxides having compositions like WO 2.96 , WO 2.9 , WO 2.72 , WO 2 , WO, and W 3 O may be formed. Temperature, kinetics, pathway and sequence of formation of these intermediate oxides have been suggested to be critically controlled by the H 2 -reduction parameters (heating rate, gas flow rate, etc.)…”

Study of an Innovative Energy Storage and Recovery System based on the W/WO3 Oxidoreduction Reaction

“…SM kb dt RT [9] Reaction rate constant k can be calculated on the basis that the velocity of the moving reaction front is constant and independent of its position in the bulk of the powder bed. If a straight line is obtained by plotting the variation of the weight over time as a function of the partial pressure of gas A, then the reaction is indeed first order and the rate constant k can be determined from the slope of the line.…”

“…If a straight line is obtained by plotting the variation of the weight over time as a function of the partial pressure of gas A, then the reaction is indeed first order and the rate constant k can be determined from the slope of the line. Equation [9] thus provides a method to determine the reaction rate constant of a first order solid-gas reaction at a given temperature by using different partial pressures of reactant gas A. Furthermore, the reaction rate constant k in equation [9] is a function of temperature and can be represented by the Arrhenius rate law:…”