Effects of ozone and produced hydroxyl radicals on the transformation of graphene oxide in aqueous media

Abstract

The hydroxyl radicals and ozone play different roles in ozonation of GO.

Pt/C Electrocatalyst Durability Enhancement by Inhibition of Pt Nanoparticle Growth Through Microwave Pretreatment of Carbon Support

“…A proof of concept on Pt/C catalyst durability enhancement from MW‐treatment of carbon support is demonstrated in the present work. Apart from the microwave treatment (to generate C−O* active sites, which is quantified by XPS), other strategies e. g. ozonation, [29] radical precursor, [30] sp 3 ‐sp 2 nanostructuring, [5d] etc., which may further increase the number of active sites on the support materials without damaging their macroscopic properties, may be further explored and is out of the scope of the current studies.…”

“…Apart from the microwave treatment (to generate Figure 7. Variations of the DLC values for the Pt/C samples subjected to stress cycling according to (a) AST1 and (b) AST2 protocols CÀ O* active sites, which is quantified by XPS), other strategies e. g. ozonation, [29] radical precursor, [30] sp 3 -sp nanostructuring, [5d] etc., which may further increase the number of active sites on the support materials without damaging their macroscopic properties, may be further explored and is out of the scope of the current studies.…”

Micro‐droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment

“…We focused on discussing the spectroscopy behaviors (i. e. UV‐Vis, Raman, and photo‐luminance) of GO in the literature, due to the easy adoption of these spectroscopy techniques in micro‐droplet trapping facility [107a,b] . In the UV‐vis spectroscopy, the comparison of GO to ozonated‐GO shows a different absorbance peak shifting from 230 nm to 210 nm (Figure 8(a)) [115] . The color of GO dispersion changes from deep brown (before) to light yellow, corresponding to the before and after ozonation respectively.…”

“…Raman spectroscopy is also a widely used technique to characterize GO. The D band (∼1350 cm −1 ) to G band (∼1580 cm −1 ) ratios have been reported to estimate the degrees of defects in GO structures (See Figure 8(b)) [115] . The higher D/G ratios are considered to be yielding more structure defects.…”

Reactivity of graphene oxide with reactive oxygen species (hydroxyl radical, singlet oxygen, and superoxide anion)

“…21,22 Additionally, HO˙was suggested as the major species responsible for decomposition of GO in solar irradiation and ozonation. [23][24][25][26] To estimate the reaction rate constant, Hou et al irradiated 100 mM H 2 O 2 to produce HO˙and measured the resulting DOC decay of GO. 10 The reported value is uncertain, however, due to coexistence of direct photolysis and HO˙reaction.…”