We report a scanning tunneling microscopy and noncontact atomic force microscopy study of close-packed 2D islands of tetrafluorotetracyanoquinodimethane (F4TCNQ) molecules at the surface of a graphene layer supported by boron nitride. While F4TCNQ molecules are known to form cohesive 3D solids, the intermolecular interactions that are attractive for F4TCNQ in 3D are repulsive in 2D. Our experim...

The design and optimization of 3D graphene nanostructures are critically important since the properties of electrochemical energy storages such as supercapacitors can be dramatically enhanced by tunable porous channels. In this work, we have developed porous graphene aerogels from graphene suspensions obtained via electrochemical exfoliation and explored their application as supercapacitor elec...

We provide a theoretical model that describes the dielectric coupling of a two-dimensional (2D) layer of graphene, represented by a polarization function in the random phase approximation, and a semi-infinite three-dimensional (3D) substrate, represented by a surface response function in a non-local formulation. We concentrate on the role of the dynamic response of the substrate for low-frequen...

Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 μM and 8.0 μA/μM, respectively. Moreover, the composite foam electrode for the sensor ...

to explore the possibility of using graphene based biosensor, adsorption of hydrogen peroxide on graphene has been investigated using density functional theory. the electronic properties of defect free and defective graphene in the presence of different number of hydrogen peroxide have been studied. the graphene with the most stable configuration defect named as sw defect is considered. the hig...

As a potential solution to concerns on sustainable energy, the wide spread commercialization of fuel cell has long been hindered by limited reserves and relatively high costs of metal catalysts. 3D graphene, a carbon-only catalyst prepared by reduction of carbon monoxide with lithium oxide, is found to electrochemically catalyze carbohydrazide oxidation reaction efficiently. A prototype of a co...

MnO2 is considered one of the most promising pseudocapactive materials for high-performance supercapacitors given its high theoretical specific capacitance, low-cost, environmental benignity, and natural abundance. However, MnO2 electrodes often suffer from poor electronic and ionic conductivities, resulting in their limited performance in power density and cycling. Here we developed a "conduct...

Biofuel cells (BFCs), which use enzymes as catalysts to harvest energy from green and sustainable fuels abundantly producible from biological systems, are promising next-generation energy devices. However, the poor stability and high specificity to only one fuel type of these bio-catalysts largely limits the practical use of current BFCs. In this contribution, we demonstrate a unique fuel cell ...

In the past two decades, extensive research and studies have been performed on graphene because of its exceptional physical properties. Owing to ultrahigh carrier mobility, quantum Hall effect unique optical transmittance, is considered be a multi-functional component for realizing next-generation optoelectronic photonic devices. Significant efforts made towards efficient synthesis, transfer, i...

We theoretically study the effective third-order nonlinear response and optical bistability of the 3D graphene based composite consisting of graphene wrapped dielectric nanoparticles embedded in dielectric host at terahertz frequencies. Taking into account the nonlinear conductivity of graphene, we derive the analytical expressions for the effective third-order nonlinear coefficient χe3 in weak...