Enhanced X-RAYS degradation of methylene blue in the presence of gold microspheres

Au@TiO2 nanocomposites synthesized by X-ray radiolysis as potential radiosensitizers

“…Particularly, a material that has consistently exhibit physical enhancement is Au, an element with high mass-energy absorption coefficient. In Figure 2.4a, a comparison between the mass energy absorption coefficient of water and Au is presented and in Figure 2.4b, the ratio between the mass energy-absorption coefficient of Au and water is presented, showing the superior photon absorption of Au with respect to water [17]. The process that follows absorption is emission, herein, electrons are emitted from the nanoparticles as a result of X-ray photons being absorbed by the atoms within the particle [18].…”

“…This solution is composed of 0.001 M FeSO4, 0.8N of H2SO4 and 0.001 M of NaCl. [17]. After irradiation, the solutions containing the synthesized Au@TiO2 nanocomposites solutions were washed with DI water using a centrifuge at 9000 rpm for 10 minutes, the water containing unreactive species was replaced with fresh DI water.…”

“…During the heating process, the deposition-precipitation method involves the deposition of Au (III) and Au (I) onto the titania surface but the deposition of these species in the presence of NaOH and urea takes place in different ways [46]. The binding process with NaOH is due to the hydroxyl groups on the surface of the support by means of either reaction shown in (17) or (18) Ti The reactions in (13) and (14) lead to the formation of a compound only formed by Au-OH species [46]. In contrast, the deposition-precipitation with urea the Au (III) species deposited onto the support surface make a strong compound containing nitrogen, oxygen, and carbon [46].…”

“…TiO2 and the photoemissions created upon interaction of Au with X-rays [3,9,17]. The excitation and ionization processes caused by the interaction of the photoemissions with the water molecules leads to the production of free radicals such as OH • , O2 -• and H + .…”

“…These species ultimately lead to cell damage. The use of Au as radiosensitizer has been proposed due to its higher photoelectric absorption cross section when compared to soft tissue and water [17]. The interaction of Au nanoparticles with X-rays results in the emission of secondary radiation such as photoelectrons,…”