PDF Publication Title:
Text from PDF Page: 095
TiO2 nanorods after hydrogen thermal treatment displayed a color change from white (GF@TiO2) to blue. This suggested that GF@TiO2:H electrode has an optical response in the visible range extending its absorption from UV into 800 nm (Figure 6.10b) in contrast to GF@TiO2 electrode, which only presents absorption in the UV region (< 400 nm). This expansion in the absorption from the UV to visible spectra could be attributed to oxygen vacancies formation in the titanium dioxide structure (bands at 441 and 486 nm), responsible for the changes in the electronic distribution, and therefore, the blue colour190,199. These defects, clearly evidenced by UV/vis absorption spectra above 500 nm, could play an important role in the electrocatalytic properties towards negative reaction in VRFB. Figure 6.11. - a) XPS Ti 2p core level spectra of the GF@TiO2 and GF@TiO2:H electrodes; b) XPS O1s core level spectra of GF@TiO2 and c) GF@TiO2:H electrode. Furthermore, we examine the change of surface chemical bonding of TiO2 induced by hydrogen thermal treatment. It was performed an X-ray photoelectron spectroscopy (XPS) measurement on both samples, i.e. GF@TiO2 and GF@TiO2:H electrodes (Figure 6.11.a). The positions of the peaks were calibrated to the graphite peak at 284.3 eV. Although both TiO2 nanorods displayed typical Ti 2p core-level XPS spectra with Ti4+ characteristics (strong Ti 2p3/2 peak at binding energy ~459.0 eV and Ti 2p1⁄2 at 464.8 eV), GF@TiO2:H electrode displayed these peaks negatively shifted, which evidences a closer Fermi level to the conduction band. Therefore, it confirms a higher electron-donor density (enhanced conductivity)200, coherent with the UV-vis information previously mentioned. However, no presence of Ti+3 have been determined from XPS spectra. The O 1s core-level XPS spectra of the GF@TiO2 and GF@TiO2:H electrodes can be convoluted in three different peaks revealing chemical structure differences between the involved materials. First, one at 530.6 eV attributed to Ti-O-Ti species. Second, another peak at 531.7 eV related to Ti-OH groups. Last, a broad band centred at 532.3 eV related to oxygen bonding to carbon on the surface 94PDF Image | Redox Flow Batteries Vanadium to Earth Quinones
PDF Search Title:
Redox Flow Batteries Vanadium to Earth QuinonesOriginal File Name Searched:
FJVG_TESIS.pdfDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Salt water flow battery technology with low cost and great energy density that can be used for power storage and thermal storage. Let us de-risk your production using our license. Our aqueous flow battery is less cost than Tesla Megapack and available faster. Redox flow battery. No membrane needed like with Vanadium, or Bromine. Salgenx flow battery
CONTACT TEL: 608-238-6001 Email: greg@salgenx.com (Standard Web Page)