Carbon Nanodots as Feedstock for a Uniform Hematite‐Graphene Nanocomposite

Abstract

High degrees of dispersion are a prerequisite for functional composite materials for applications in electronics such as sensors, charge and data storage, and catalysis. The use of small precursor materials can be a decisive factor in achieving a high degree of dispersion. In this study, carbon nanodots are used to fabricate a homogeneous, finely dispersed Fe2O3‐graphene composite aerogel in a one‐step conversion process from a precursor mixture. The laser‐assisted conversion of small size carbon nanodots enables a uniform distribution of 6.5 nm Fe2O3 nanoparticles during the formation of a highly conductive carbon matrix. Structural and electrochemical characterization shows that the features of both material entities are maintained and successfully integrated. The presence of Fe2O3 nanoparticles has a positive effect on the active surface area of the carbon aerogel and thus on the capacitance of the material. This is demonstrated by testing the performance of the composite in supercapacitors. Faradaic reactions are exploited in an aqueous electrolyte through the high accessible surface of the incorporated small Fe2O3 nanoparticles boosting the specific capacitance of the 3D turbostratic graphene network significantly.

Patching laser-reduced graphene oxide with carbon nanodots

“…1. [23][24][25][26] To ensure equal mass loading throughout the samples on the substrates prior to the laser-reduction step, the amount of applied solution was adjusted accordingly (Table 1). Solutions were either prepared in H 2 O or in a 1 : 1 mixture of N-methyl-2pyrrolidone (NMP) and iso-propanol (i-PrOH) (NMP/i-PrOH (1 : 1 v/v)) to produce uniform films.…”

“…[17][18][19][20] A particularly interesting approach is the direct laserassisted conversion of graphene oxide (GO) or carbon nanodots (CNDs). [21][22][23][24][25][26][27] In the past years, laser-reduction of GO has been studied as a versatile method to fabricate and micropattern nanoelectronic devices. 28 Laser-reduced GO is composed of randomly oriented single graphene sheets that are partially stacked with specific surface areas (SSA) of 800-1500 m 2 g −1 .…”

“…[29][30][31][32] Moreover, they act as suitable starting materials for uniform functional composite materials. 25 In general, CNDs and GO can be considered related materials. Both consist of two-dimensional π-conjugated carbon with oxygen containing functional groups.…”

Graphene's Role in Emerging Trends of Capacitive Energy Storage

“…Within one conversion, a composite aerogel formed. [54] The laser-assisted method generated an array of uniform Fe 2 O 3 nanoparticles with diameters around 6.5 nm and simultaneously formed a highly conductive carbon foam. The Fe 2 O 3 nanoparticles not only enhanced the specific surface area of the aerogel materials, but also introduced pseudocapacitance.…”

Laser‐Assisted Lattice Recovery of Graphene by Carbon Nanodot Incorporation

“…The de‐oxidation process separated the graphene sheets, so they were exposed rather than being stacked one on top of the other. The product of this method was thoroughly studied in previous papers . Some of these data including a few physical properties of the product, are presented in the Supporting Information in Table S1 and Figure S1.…”