Solar photocatalytic degradation of dyes: high activity of combustion synthesized nano TiO2

The valence and site occupancy of substituting metals in magnetite spinel structure Fe3−xMxO4 (M = Cr, Mn, Co and Ni) and their influence on thermal stability: An XANES and TG-DSC investigation

“…This suggests that the incorporation of these metal cations increases the surface hydroxyl amount. The surface hydroxyl groups are functional groups of iron oxides due to its vital role in surface adsorption [49], photocatalysis [50] and surface acidity (Br4nsted acid) [51]. Under dry conditions, surface Fe cations may be unsaturated in coordination.…”

A comparative study about the effects of isomorphous substitution of transition metals (Ti, Cr, Mn, Co and Ni) on the UV/Fenton catalytic activity of magnetite

“…For substituted magnetite samples, both the broadening of diffraction lines at ca. [28][29][30][31][32][33][34][35][36][37][38][39] • and the shift of peaks at ca. 35.5 • toward lower diffraction angle indicate the incorporation of substituting metals into inverse spinel structure, which is resulted from the difference in ionic radii between iron and substituting metal cations (Table 1) [21].…”

“…The surface hydroxyl groups are functional groups of iron oxides, due to its vital role in surface adsorption [37], photocatalysis [38] and surface acidity (Brønsted acid) [39]. The incorporation of substituting metals resulted in a slight distortion of magnetite lattice and accordingly increased the surface hydroxyl amount [40].…”

Temperature and reaction time effects on the structural properties of titanium dioxide nanopowders obtained via the hydrothermal method

“…Different methods have been employed for the synthesis of titanium dioxide, as follows: chemical precipitation (Pedraza and Vasquez, 1999;Scolan and Sanchez,1998), the sol-gel method (Gartner et al, 2004;Su et al, 2006b), hydrothermal (Wu et al, 2002) and solvothermal processes (Kim et al, 2003;Yin et al, 2003), combustion method (Nagaveni et al, 2003), a microemulsion-mediated process (Hong et al, 2003), electrochemical synthesis , fungus-mediated synthesis (Jha et al, 2009) and chemical vapour deposition (CVD) (Jones and Chalker 2003). Venkatachalam et al (2007) reported the preparation of titanium dioxide nanoparticles via the sol-gel method with different reaction parameters, such as different hydrolyzing agents, molar ratio, aging time and calcination temperature.…”