Six Mo/TiO2 samples (with 0, 1.0, 2.5, 5.0, 7.5, and 10 wt % Mo nominal contents) were obtained by reverse micelle sol-gel synthesis, followed by calcination at 500 °C. The samples were characterized by means of powder X-ray Diffraction (PXRD), quantitative phase analysis as obtained by Rietveld refinement, field-emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray analysis, N2 adsorption/desorption at -196 °C, X-ray photoelectron spectroscopy, and diffuse reflectance (DR) UV-vis spectroscopy. As a whole, the adopted characterization techniques showed the inclusion of a sizeable Mo amount, without the segregation of any MoOx phase. Specifically, PXRD showed the occurrence of anatase and brookite with all the studied samples; notwithstanding the mild calcination temperature, the formation of rutile occurred at Mo wt % ≥2.5 likely due to the presence of brookite favoring, in turn, anatase to rutile transition. DR UV-vis and XP spectroscopies allowed determining the samples' band gap energy (Eg) and valence band energy, respectively, from which the conduction band energy was calculated; and the observed Eg value increase at 10 wt % Mo was ascribed to the Moss-Burstein effect.
Effective Inclusion of Sizable Amounts of Mo within TiO2Nanoparticles Can Be Obtained by Reverse Micelle Sol-Gel Synthesis
Esposito S.;Dell'Agli G.;
2021-01-01
Abstract
Six Mo/TiO2 samples (with 0, 1.0, 2.5, 5.0, 7.5, and 10 wt % Mo nominal contents) were obtained by reverse micelle sol-gel synthesis, followed by calcination at 500 °C. The samples were characterized by means of powder X-ray Diffraction (PXRD), quantitative phase analysis as obtained by Rietveld refinement, field-emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray analysis, N2 adsorption/desorption at -196 °C, X-ray photoelectron spectroscopy, and diffuse reflectance (DR) UV-vis spectroscopy. As a whole, the adopted characterization techniques showed the inclusion of a sizeable Mo amount, without the segregation of any MoOx phase. Specifically, PXRD showed the occurrence of anatase and brookite with all the studied samples; notwithstanding the mild calcination temperature, the formation of rutile occurred at Mo wt % ≥2.5 likely due to the presence of brookite favoring, in turn, anatase to rutile transition. DR UV-vis and XP spectroscopies allowed determining the samples' band gap energy (Eg) and valence band energy, respectively, from which the conduction band energy was calculated; and the observed Eg value increase at 10 wt % Mo was ascribed to the Moss-Burstein effect.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
