The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inha...The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.展开更多
Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace r...Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace reducing gases such as SO2 in the atmosphere,leading to different environmental and health effects. In this paper, the heterogeneous reaction process between O3-aged BC and SO2 was explored via in-situ diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）. Combined with ion chromatography（IC）,DRIFTS was used to qualitatively and quantitatively analyze the sulfate product. The results showed that O3-aged BC had stronger SO2 oxidation ability than fresh BC, and the reactive species/sites generated on the surface had an important role in the oxidation of SO2.Relative humidity or 254 nm UV（ultraviolet） light illumination enhanced the oxidation uptake of SO2 on O3-aged BC. The oxidation potentials of the BC particles were detected via dithiothreitol（DTT） assay. The DTT activity over BC was decreased in the process of SO2 reduction, with the consumption of oxidative active sites.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21307142 and 21403261)Ningbo Science and Technology Bureau(No.2014D10004)
文摘The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.
基金the financial support provided by the National Natural Science Foundation of China(Nos.21277004,21190051,41121004)the Beijing Natural Science Foundation(No.8132035)+1 种基金the Fujitsu Laboratories Limited Foundation(No.k120400)the Special Fund of State Key Joint Laboratory of Environmental Simulation and Pollution Control(2015)
文摘Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace reducing gases such as SO2 in the atmosphere,leading to different environmental and health effects. In this paper, the heterogeneous reaction process between O3-aged BC and SO2 was explored via in-situ diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）. Combined with ion chromatography（IC）,DRIFTS was used to qualitatively and quantitatively analyze the sulfate product. The results showed that O3-aged BC had stronger SO2 oxidation ability than fresh BC, and the reactive species/sites generated on the surface had an important role in the oxidation of SO2.Relative humidity or 254 nm UV（ultraviolet） light illumination enhanced the oxidation uptake of SO2 on O3-aged BC. The oxidation potentials of the BC particles were detected via dithiothreitol（DTT） assay. The DTT activity over BC was decreased in the process of SO2 reduction, with the consumption of oxidative active sites.
