caa a22 4500 606173862 CHVBK 20210128100735.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s11244-015-0391-z doi (NATIONALLICENCE)springer-10.1007/s11244-015-0391-z Sonication-Free Exfoliation of Graphite Oxide via Rapid Phase Change of Water [Elektronische Daten] [Isao Ogino, Yuya Yokoyama, Shin Mukai] Efficacy of a new approach for the synthesis of graphene oxide (GO) nanosheets that has been recently reported (Ogino et al. in Chem Mater 26:3334-3339, 2014) was investigated further using graphite oxides with various degrees of oxidation and average particle sizes. The approach consists of rapid freeze-thaw cycles of water containing graphite oxide, which enables the efficient exfoliation of graphite oxide layers with the minimal fragmentation of GO sheets. The method is effective for the exfoliation of graphite oxides with C/O atomic ratios ≤2.6 as shown by experiments with various degrees of oxidation of graphite oxides. When this method was tested for large particle-size graphite oxide that had been prepared from graphite with the average particle size of 60μm, it formed approximately tenfold larger GO sheets than those prepared using sonication. Exfoliation experiments conducted at different freezing rates of water demonstrate that a faster freezing rate of water yielded a higher concentration of a dispersed GO solution. Thus, the results support the hypothesis that rapid phase change enables efficient layer exfoliation. Springer Science+Business Media New York, 2015 Graphene oxide nationallicence Graphene nationallicence Exfoliation nationallicence Delamination nationallicence Ogino Isao Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, 060-8628, Sapporo, Japan aut Yokoyama Yuya Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, 060-8628, Sapporo, Japan aut Mukai Shin Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, 060-8628, Sapporo, Japan aut Topics in Catalysis Springer US; http://www.springer-ny.com 58/7-9(2015-05-01), 522-528 1022-5528 58:7-9<522 2015 58 11244 https://doi.org/10.1007/s11244-015-0391-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11244-015-0391-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ogino Isao Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, 060-8628, Sapporo, Japan aut NATIONALLICENCE 700 1- Yokoyama Yuya Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, 060-8628, Sapporo, Japan aut NATIONALLICENCE 700 1- Mukai Shin Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, 060-8628, Sapporo, Japan aut NATIONALLICENCE 773 0- Topics in Catalysis Springer US; http://www.springer-ny.com 58/7-9(2015-05-01), 522-528 1022-5528 58:7-9<522 2015 58 11244