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The graphene-based materials are promising for applications in supercapacitors and other energy storage devices due to the intriguing properties, i.e., highly tunable surface area, outstanding electrical conductivity, good chemical stability, and excellent mechanical behavior. This review summarizes recent development on graphene-based materials for supercapacitor electrodes, based on their macrostructural complexity, i.e., zero-dimensional (0D) (e.g., free-standing graphene dots and particles), one-dimensional (1D) (e.g., fiber-type and yarn-type structures), two-dimensional (2D) (e.g., graphenes and graphene-based nanocomposite films), and three-dimensional (3D) (e.g., graphene foam and hydrogel-based nanocomposites). There are extensive and on-going researches on the rationalization of their structures at varying scales and dimensions, development of effective and low-cost synthesis techniques, design and architecturing of graphene-based materials, as well as clarification of their electrochemical performance. There are several methods for producing graphene, each with its own advantages and disadvantages. Graphene-based materials have great potential to be employed in supercapacitors due to their unique two-dimensional structure and inherent physical properties like excellent electrical conductivity and large area. This text summarizes recent developments within the sector of supercapacitors, including double-layer capacitors and quasi-capacitors. The pros and cons of using them in supercapacitors are discussed. Compared to traditional electrodes, graphene-based materials show some new properties and mechanisms within the method of energy storage and release. During this paper, we briefly describe carbon structures, particularly graphene, and also the history of graphene discovery, and briefly describe the synthesis methods, properties, characterization methods, and applications of graphene. [ABSTRACT FROM AUTHOR]

Air pollution is known as one of the most important causes of death in the whole world. Therefore, pollution reduction to achieve clean air was noticed by everyone. This way, using nanotechnology to control air and monitor is a novel approach. This paper investigates the effect of the number of graphene nano-pores on the SiO 2 separation from the H 2 O vapour in the presence of an external electric field with the magnitude of 0.01 V/Å using the molecular dynamics (MD) method. The electric field affects the charged particles and causes disturbance in the structure. It also prevents SiO 2 nanoparticles from passing through the graphene nanosheet. Also, the presence of carbon nanosheets acts as a membrane and affects the diffusion of water in the nanostructure. So, the results show that in the presence of a nano-pore, the number of H 2 O molecules reaches to 496 and 568 in reservoirs 2 and 3. Also, the number of SiO 2 nanoparticles reaches 10 and 4 in reservoirs 2 and 3. This shows that in reservoirs 2 and 3, about 80% and 60% of the SiO 2 nanoparticles are separated. As mentioned before, the electric field prevents the passage of SiO 2 nanoparticles through the graphene nanosheet. As the number of graphene nano-pores increases by 2, 3, 4, and 5, the number of passing water molecules increases. Considering that the number of graphene nano-pores has increased and the movement path of particles has increased, the number of passing particles almost increases. However, the electric field prevents the passage of SiO 2 nanoparticles. According to the results, the suggested setup can be employed for designing highly efficient nanostructured membranes for air purification and monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

This study describes the mechanical behavior of a brick structure by inserting graphene nano-sheet (GNS) into this construction material using the Molecular Dynamics (MD) approach. Technically, we utilized Universal Force Field (UFF) and Tersoff Force Field (TFF), respectively, to simulate ideal brick (pristine brick) and graphene structures. The consequence of the equilibrium procedure of atomic structures indicates their suitable physical stability, which emerges from the proper MD simulation settings. Technically, to characterize the mechanical properties (MP) of pristine brick matrix (PBM) and reinforced brick-graphene (RBG) nanocomposite, some parameters like Stress-Strain (S–S) Curve, Young's modulus (YM), and Ultimate Strength (US) of a pristine compound, and reinforced structure are mentioned. Numerically, by inserting the GNS into the PBM with a 5% atomic ratio, Young's modulus of simulated nanostructure reaches 3379 MPa, and the US of brick increases to 19.14 MPa. These simulation results show the important effect of GNS on the MP of the PBM, which is suitable for construction applications such as cologne arches. • We investigated the mechanical behavior of brick structure by inserting Graphene nanosheets. • Stress-strain curve, Young's modulus, and ultimate strength of pristine compound and reinforced structure were reported. • Young's module reaches to 3379 MPa and the ultimate strength of brick increases to 19.14 MPa. • TResults show the effect of graphene nanosheets on mechanical properties. [ABSTRACT FROM AUTHOR]

Graphene is one of the most important two-dimensional carbon allotropes with a plate structure similar to honeycomb nets. Due to its high thermal conductivity (TC), it is an excellent material for the thermal management of electronic nano-components. Investigating and obtaining thermal attributes of graphene for use and replacement in electronic components to study the cooling of parts is one of the important topics discussed by researchers. This research investigates monolayer graphene (MG) and helical graphene (HG). First, the TC of MG is calculated and compared using the equilibrium method (Green-Kubo) and the non-equilibrium method. The produced graphene sheets are usually not perfect and have various defects affecting graphene's thermal and mechanical attributes. Then, the impact of nitrogen doping defect on the TC of MG is investigated. In addition, three samples of HG in different dimensions are simulated using the non-equilibrium method. The TC for each of these samples is obtained and compared. Finally, as an innovation of this research, simulated graphene coated with hydrogen atoms and TC are calculated for this model. The results show that nitrogen doping in the graphene structure reduces the amount of TC. The TC of HG depends on the effective length of the structure and the cross-sectional area of the structure. Also, the TC was reduced by hydrogenating the HG structure. [Display omitted] [ABSTRACT FROM AUTHOR]