Photocatalytic, Morphological and Structural Properties of the TiO2-SiO2-Ag Porous Structures Based System

Abstract

TiO2-SiO2-based nanocomposites with highly porous structures are gaining ever increasing attention due to their specific properties and large variability of synthesis pathways together with wide information on the impact of the synthesis on the activity of the catalyst. This thereby offers an alternative approach to traditional/commercially available photocatalysts. In our work TiO2-SiO2 based aerogels were obtained and modified with various amount of Ag nanoparticles, using different synthesis pathways. In the first instance their photocatalytic activity was examined in detail, by observing major differences toward salicylic acid and correlating them with their morphological and structural properties (investigating their mesoporous character, band-gap values, crystallinity grade etc.). Applying different techniques such as diffuse reflectance spectroscopy (DRS), X-ray diffraction measurements (XRD), transmission electron microscopy (TEM), Raman- and X-ray photoelectron spectroscopy (XPS) the nanoparticles and their composite morphological and structural details were successfully evaluated. Major differences were observed in the activity towards salicylic acid.

Room-temperature pulsed CVD-grown SiO2 protective layer on TiO2 particles for photocatalytic activity suppression

“…The O 1s spectrum of the SiO 2 -coated TiO 2 shows a noticeable difference with an intense peak at 532.69 eV, representing the Si-O chemical state in SiO 2 . 39 The tted spectrum also reveals the presence of additional components located at 534.5 eV (Si-O x ) and 531.64 eV (Si-O-Ti). 39 No signicant change was observed for the Ti 2p spectra of uncoated and SiO 2 -coated TiO 2 particles.…”

“…39 The tted spectrum also reveals the presence of additional components located at 534.5 eV (Si-O x ) and 531.64 eV (Si-O-Ti). 39 No signicant change was observed for the Ti 2p spectra of uncoated and SiO 2 -coated TiO 2 particles. In addition, no considerable amount of Cl contamination was detected by XPS, suggesting the complete consumption of -Cl by the chemical reactions with H 2 O.…”

Hierarchically structured polymeric ionic liquids and polyvinylpyrrolidone mat-fibers fabricated by electrospinning

“…S17 †). 64,65 The calculated value was 2.42 eV (513 nm). 66 This result is in agreement with the size of the AuNPs measured by TEM (6.96 AE 5.2 nm) and similar to those obtained for related polymeric composites obtained by reduction with aqueous NaBH 4 .…”

Preparation of TiO2/WO3 composite photocatalysts by the adjustment of the semiconductors' surface charge

“…In order to maximize the lifetime of these charges, various approaches can be considered: (i) depositing of noble-metals [6,7], (ii) creating composites with other semiconductors [8,9], (iii) and the use of carbon nanomaterials [10,11]. To obtain these composites several methods are available, like impregnation, physical mixing, in-situ synthesis, but none of the methods listed above is an efficient alternative for achieving high number of interparticle contacts between the components.…”