Nanocarbon Composites and Hybrids in Sustainability: A Review

Abstract

There is an ever-growing need to protect our environment by increasing energy efficiency and developing "clean" energy sources. These are global challenges, and their resolution is vital to our energy security. Although many conventional materials, such as metals, ceramics, and plastics, cannot fulfil all requirements for these new technologies, many material combinations can offer synergistic effects that create improved and even new properties. The implementation of nanocarbons, such as graphene and carbon nanotubes, into nanocomposites and, more recently, into the new class of hybrids, are very promising examples. In contrast to classical nanocomposites, where a low volume fraction of the carbon component is mixed into a polymer or ceramic matrix, hybrids are materials in which nanocarbon is coated with a thin layer of the functional compound, which introduces the interface as a powerful new parameter. Based on interfacial charge and energy transfer processes, nanocarbon hybrids have shown increased sensitivities in gas sensors, improved efficiencies in photovoltaics, superior activities in photocatalysts, and enhanced capacities in supercapacitors. This review compares the characteristics and potentials of both nanocarbon composites and hybrids, highlights recent developments in their synthesis and discusses key challenges for their use in various energy applications.

New nanocomposite proton conducting membranes based on a core–shell nanofiller for low relative humidity fuel cells

“…As the concentration of the ZrTa nanofiller increases, changes in the vibrational spectra due to the presence of the filler are evident below ca. 1150 cm 21 . A comparison of the spectra of the ZrO 2 and Ta 2 O 5 oxoclusters and the side B spectra shows that the presence of new bands in this region is associated with the filler.…”

“…6. The peak centered at 1470 cm 21 , which is present in dry Nafion but is absent in the l = 3 (where the proton is dissociated due to the presence of water molecules solvating the sulfonic acid groups) and Na + -neutralized Nafion spectra, is assigned here to the OH bending mode, d(OH), of the -SO 3 H moiety. This peak is typically not reported in the literature and is generally only seen in very dry conditions due to the dissociation of the acidic proton in the presence of even small amounts of water (l .…”

“…As an example, Pereira reports that at T = 80 uC and at RH = 98%, Nafion112 TM and a hybrid Nafion-silica membrane are characterized by a conductivity of ca. 15 and 25 mS cm 21 , respectively. 39 The hybrid membrane is also better able to absorb the available water, which leads to significantly better performance at low hydration degrees because the membrane maintains sufficient proton conductivity.…”

Hybrid systems based on metal oxide and nanocarbons: electronic properties and applications for photocatalysis

“…[Vilatela and Eder 2012] In a composite material, its properties are the sum of the intrinsic properties of each component. However, it does not have the ideal properties due to poor interfacial area of the composite material.…”

“…This can be achieved by two routes: ex-situ and in-situ synthetic approaches. [Vilatela and Eder 2012;Eder 2010;Shearer et al 2014] In the ex-situ route, also known as the building block approach, the two components are synthesised separately and then attached using covalent, non-covalent or electrostatic interactions (Figure 2.4). This strategy has been used to successfully link nanoparticles [Yeh et al 2009], quantum dots [Das et al 2014], polymers [Gegenhuber et al 2015] and biomolecules, especially proteins [Kuila et al 2010].…”