کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1480978 1510437 2014 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Properties of HO2• radicals induced by γ-ray irradiation in silica nanoparticles
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Properties of HO2• radicals induced by γ-ray irradiation in silica nanoparticles
چکیده انگلیسی


• We have irradiated O2-loaded silica nanoparticles generating HO2 radicals.
• We have proved a peculiar generation process of HO2 in silica nanoparticles.
• H atoms arise from the breaking of H2O molecules surrounding the nanoparticles.
• We found a new conversion factor to estimate the O2 content in silica nanoparticles.

We report an experimental investigation on the effects of γ-ray irradiation in several types of silica nanoparticles previously loaded with O2 molecules. They differ in specific surface and average diameter. By electron paramagnetic resonance (EPR) measurements we observe the generation of about 1018 HO2
• /cm3 interstitial radicals. These radicals are induced by reaction of interstitial O2 molecules with radiolytic H atoms, as previously suggested for O2-loaded bulk a-SiO2 samples. However, at variance with respect to bulk materials, our experimental evidences suggest a different generation process of HO2
• radical. In fact, by a detailed study of samples exposed to D2O, our results prove that radiolytic hydrogen atoms reacting with O2 to produce HO2
• mainly arise from a radiation induced breaking of H2O molecules in the layers surrounding the nanoparticles or in the interstices. Also, by the correlation of HO2
• paramagnetic centers concentration, determined by EPR measurements, and O2 Raman/PL signal we further considered the issue of the direct estimation of the O2 concentration in silica nanoparticles from Raman/PL spectra giving an independent conversion factor (the ratio between these latter two quantities), which is in good agreement with those previously proposed by other authors basing on optical measurements.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 405, 1 December 2014, Pages 116–123
نویسندگان
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