Hypergolics in Carbon Nanomaterials Synthesis: New Paradigms and Perspectives

Abstract

Recently we have highlighted the importance of hypergolic reactions in carbon materials synthesis. In an effort to expand this topic with additional new paradigms, herein we present novel preparations of carbon nanomaterials, such-like carbon nanosheets and fullerols (hydroxylated fullerenes), through spontaneous ignition of coffee-sodium peroxide (Na2O2) and C60-Na2O2 hypergolic mixtures, respectively. In these cases, coffee and fullerenes played the role of the combustible fuel, whereas sodium peroxide the role of the strong oxidizer (e.g., source of highly concentrated H2O2). The involved reactions are both thermodynamically and kinetically favoured, thus allowing rapid product formation at ambient conditions. In addition, we provide tips on how to exploit the released energy of such highly exothermic reactions in the generation of useful work.

Nanocarbon from Rocket Fuel Waste: The Case of Furfuryl Alcohol-Fuming Nitric Acid Hypergolic Pair

“…Furthermore, they show some additional ways of exploiting the released energy from hypergolic reactions that are complementary to the chemical, thermoelectric, or photovoltaic work presented elsewhere [ 15 , 17 , 18 ]. Hence hypergolics not only enables an operationally simple carbon synthesis but also gives off useful energy in the process.…”

“…Recently our group has introduced hypergolic reactions as a new and general synthesis tool towards the formation of a variety of functional carbon materials (nanosheets, crystalline graphite, carbon dots, fullerols, hollow spheres, and nanodiscs) [ 15 , 16 , 17 , 18 , 19 , 20 ]. Hypergolic synthesis presents certain advantages over conventional carbonization methods (pyrolysis, hydrothermal, chemical vapor deposition—CVD) for two main reasons.…”

“…This clearly differentiates from pyrolytic, hydrothermal, or CVD methods that require higher temperature in order to operate synthesis and extract carbon from its precursors (i.e., an energy-consuming process). In fact, we have previously demonstrated that the energy released from hypergolic reactions could be directly converted into useful chemical, thermoelectric, or photovoltaic work [ 15 , 17 , 18 ]. Therefore, hypergolics allows a fast and spontaneous carbon synthesis at ambient conditions in an energy-liberating manner without external stimuli (heat, spark, or mechanical shock).…”

Carbon Nanostructures Derived through Hypergolic Reaction of Conductive Polymers with Fuming Nitric Acid at Ambient Conditions

“…Recently, our group has introduced hypergolic reactions as a novel synthesis tool towards the rapid and spontaneous preparation of a large variety of functional carbon nanomaterials at ambient conditions. For example, carbon nanosheets were previously obtained from self-ignition of lithium dialkylamides in air [ 11 ], highly crystalline graphite through the spontaneous reaction of the acetylene-chlorine hypergolic mixture [ 12 ], carbon dots or nanosheets via hypergolic pairs based on Girard’s reagent T or nitrile rubber and fuming nitric acid as strong oxidizer [ 6 ], carbon nanosheets or hydroxylated fullerenes using coffee grains or C 60 as carbon sources and sodium peroxide as strong oxidizer [ 13 ], dense or hollow spheres derived from the reaction of ferrocene with liquid bromine at room temperature [ 14 ], carbon nanodiscs obtained through the cyclopentadienyllithium-fuming nitric acid hypergolic pair [ 15 ] and, lastly, carbon nanosheets via the hypergolic reaction of furfuryl alcohol with fuming nitric acid at ambient conditions [ 16 ]. In the majority of the reactions the released energy was converted into useful chemical [ 11 ], thermoelectric [ 6 ], photovoltaic [ 13 ] or mechanical [ 16 ] work.…”

Rapid Carbon Formation from Spontaneous Reaction of Ferrocene and Liquid Bromine at Ambient Conditions

“…An old yet classic example refers to the exothermic carbonization of sugar by concentrated sulfuric acid. Most recently, hypergolic reactions were successfully utilized from our group for the spontaneous and fast preparation of a variety of functional carbon materials, such as carbon nanosheets, crystalline graphite, graphitic carbon nitride, photoluminescent carbon dots, and fullerols, at ambient conditions [2][3][4][5]. By definition, in hypergolic reactions two reagents react immediately and energetically upon contact.…”