Nanographite Synthesized from Acidified Sucrose Microemulsions under Ambient Conditions

Natasha J Hargreaves,Sharon J Cooper

doi:10.1021/acs.cgd.5b01753

Abstract

We show here that nanographite can be synthesized at room temperature and pressure through a simple process of acidifying sucrose microemulsions. This is in contrast to conventional wisdom, which stipulates that graphite can only be produced using high temperatures. Natural graphite arises via progressive metamorphisms of carbonaceous material subjected to temperatures above ∼600 K and pressures >2 kbar. Synthetic pyrolytic graphite requires temperatures >2500 K, and even nanographite formation from amorphous carbons requires temperatures >850 K. Our synthesis route utilizes the dehydration of sucrose by concentrated sulfuric acid, a variant of the well-known carbon black snake experiment, which produces an amorphous carbonaceous product. Crucially, though, we conduct the reaction in nanometer-sized microemulsion droplets to exert control over the reaction and sheet stacking process. This ensures that only sufficiently pristine graphene nanosheets can stack, thereby producing nanographite in a simple one-...

Highlights

Graphite is a crystalline allotrope of carbon that is thermodynamically stable under ambient conditions and consists of stacked graphene layers
Graphene is a zero band gap semiconductor material with intrinsic properties of remarkable charge mobility, high mechanical strength, and excellent thermal conductivity. These attributes may deliver significant benefits in areas such as optoelectronics, energy storage, and molecular sensing either intrinsically or through doping.[1−4] It is widely accepted that graphite synthesis requires ultrahigh temperatures or a combination of high temperature and pressure
Natural graphite arises via progressive metamorphisms of carbonaceous material subjected to temperatures above ∼600 K and pressures >2 kbar with the degree of crystallinity correlated with increasing metamorphic grade.[5]

Summary

Introduction

Graphite is a crystalline allotrope of carbon that is thermodynamically stable under ambient conditions and consists of stacked graphene layers. Graphene is a zero band gap semiconductor material with intrinsic properties of remarkable charge mobility, high mechanical strength, and excellent thermal conductivity. These attributes may deliver significant benefits in areas such as optoelectronics, energy storage, and molecular sensing either intrinsically or through doping.[1−4] It is widely accepted that graphite synthesis requires ultrahigh temperatures or a combination of high temperature and pressure. Nanographite can be formed by heating amorphous carbons but even here temperatures >850 K are required.[7]

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