Supercritical alcohols as solvents and reducing agents for the synthesis of reduced graphene oxide

Controllable synthesis of reduced graphene oxide

“…Dreyer et al [29] reported a mild reduction of GO with various alcohols by heating at reflux for 5 days, and a high carbon-to-oxygen (C/O) atomic ratio of 30 and bulk powder conductivities as high as 4600 S m -1 were achieved when benzyl alcohol was used as a neat reductant. Seo and co-workers [23] investigated the effect of supercritical alcohols on the properties of the resulting graphene. The results showed that the RGO reduced by supercritical ethanol exhibited a higher C/O atomic ratio of 14.4 and a larger surface area of 203 m 2 /g in comparison with those RGOs reduced by the other supercritical alcohols.…”

“…To date, researchers have studied a number of chemical reductants to reduce GO, for example, anhydrous hydrazine [19], hydrazine monohydrate [20] and sodium borohydride [21]. However, the above mentioned reducing agents are possession of high toxicity and explosion hazard [22], which makes them unattractive for production of reduced graphene oxide (RGO) in large-scale [23]. Hence, seeking a safer, lower or non-toxic reductants for controllable reduction of graphene oxide in a single step is demanded.…”

“…Hence, seeking a safer, lower or non-toxic reductants for controllable reduction of graphene oxide in a single step is demanded. Very recently, many efforts have been devoted to study green reductants for preparation of RGO, such as water [24], L-ascorbic acid [25,26], birch [27], alcohols [23,28,29], and so on. Among these agents, alcohols have shown a special attraction due to their inherent reduction power or the ability to donate M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 hydrogen [23].…”

“…Very recently, many efforts have been devoted to study green reductants for preparation of RGO, such as water [24], L-ascorbic acid [25,26], birch [27], alcohols [23,28,29], and so on. Among these agents, alcohols have shown a special attraction due to their inherent reduction power or the ability to donate M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 hydrogen [23]. Su and co-workers [28] fabricated graphene via alcohol reduction (at 900 o C with Ar as a carrier gas), alcohol/H 2 reduction (at 900 o C with 20% H 2 /Ar as a carrier gas) and other two reduction methods, respectively.…”

Ultra-simple synthetic approach to the fabrication of CeO2–ZrO2 mixed nanoparticles into homogeneous, domain, and core–shell structures in mesoporous spherical morphologies using supercritical alcohols

“…S1), with the use of supercritical methanol as the 5 reaction medium [23,24]. In addition, we have synthesized several MARIMO families, such as SiO 2 , ZnO, ZrO 2 , and CeO 2 using a similar synthetic approach with supercritical alcohols [25], being versatile media for many functional material synthesis [26][27][28]. The obtained MARIMO NPs show almost complete spherical morphology in solid and hollow structures, well-defined pore topology, large surface area, mono-dispersion ability, and excellent thermal stability, and allow for easy manipulation, which would be promising functional materials for many applications, such as catalysis, lapping and polishing, material storage and slow release, drug and gene delivery, and solar energy conversion, etc.…”