Sharif Digital Repository

The design of 3-dimensional (3-D) nanostructured materials on the novel current collectors has recently considered as a promising strategy for developing high-performance supercapacitors. Herein, in the first step, a novel 3-D nickel nanocone arrays (NCAs) are synthesized on the surface of nickel plate (NP) by a one-step electrodeposition method without using any template (NCAs-NP). Then, a simple and efficient method is developed for fabricating ternary metal sulfides electrodes based on the electrodeposition of nickel cobalt iron sulfide (Ni-Co-Fe-S) ultrathin nanosheets on the surface of NCAs-NP. Taking advantages of the unique flower like structure of Ni-Co-Fe-S ultrathin nanosheets and... 

A high performance asymmetric supercapacitor (ASC)has been fabricated by using nickel oxide-cobalt oxide nanosheets (NiO–CoO NSs), which were directly grown on carbon nanotubes (CNTs)and hydrothermal carbon spheres (HTCs)as positive and negative electrodes, respectively. Both electrode materials are binder-free prepared by using a catalytic chemical vapour deposition (CVD)approach followed by a facile hydrothermal method for cathode and a one-step environmental-friendly route called hydrothermal carbonization for anode. Using NiO–CoO NSs@CNTs and HTCs, which were directly grown on Ni foam, not only leads to a very small equivalent series resistance, but also provides an impressive capacitive... 

Recently, graphitic carbon nitride (g-C3N4) has attracted great interest for photo(electro)chemical applications such as sensing, solar energy exploitation, photocatalysis, and hydrogen generation. This paper presents the potential application and benefits of g-C3N4 nanolayers as a green and highly efficient electrode modifier for the detection of trace lead ions in drinking water and urban dust samples. Carbon nitride nanosheets with a thickness of ∼6 A° and lateral of 100–150 nm were prepared through high-temperature polymerization of melamine followed by sonication-assisted liquid exfoliation. A glassy carbon electrode (GCE) was modified by a thin layer of g-C3N4 through drop casting and... 

High-performance supercapacitors that merit superior power and energy densities, as well as long-term cycle durability are always of great significance as a building block of energy storage devices. Herein, an innovative strategy is developed to design hierarchical and unique porous structures of ternary metal sulfide nano-flake decorated porous hydrothermal carbon microspheres. Hierarchical microspheres of ternary zinc-cobalt sulfide nanosheet (NS) decorated biomass derived hydrothermal carbon spheres (HTCSs) are directly employed as the positive supercapacitor electrodes. In addition, composites of pyrolyzed polyaniline nanotubes (PPNTs) and iron oxide, receiving advantages from highly... 

The construction of binary and ternary heterojunctions has gathered attention in water remediation applications. Herein, g-C3N4, MIL-101(Fe), and MIL-101(Fe)/g-C3N4 binary composite were synthesized by in-situ growth of MIL-101(Fe) crystals along with the nanosheets of g-C3N4. The materials have been characterized by XRD, FTIR, SEM, EDS, DRS, PL, and BET/BJH. The highest degradation efficiency achieved using MIL-101(Fe)/g-C3N4 nanocomposite was 99.3% while the pristine g-C3N4 degraded only 40% of the pollutants by photocatalyst dosage = 0.005 g, pH = 4.8, and irradiation time = 90 min condition. This enhanced photocatalytic performance might be attributed to improved optical properties and... 

Heat pipes are useful devices in heat transfer and particularly, in cooling systems. Given the high demand for cooling systems in various applications, an improvement in the performance of heat pipes has gained much attraction in recent years. In this study, the effects of utilizing working fluids with different thermal properties on the performance of pulsating heat pipes (PHP) are experimentally studied. Hence, nano-encapsulated phase change material (NPCM), reduced graphene oxide nanosheets, and their mixture, as a novel hybrid nanofluid, are prepared and dispersed in water as a working fluid. NPCM at 3 concentrations of 5, 10, and 20 g/L, as well as nanosheets at three concentrations of... 

During oil and gas well drilling, the filtration control of bentonite water-based drilling fluids (BT-WBDFs), as an environmentally friendly fluid, is crucial to avoid formation damage and swelling shale problems. One of the most critical problems is undesirable changes in the rheology and filtration properties of the BT-WBDFs because of salt contamination. Herein, the potential of using both graphene oxide (GO) nanosheets and a graphene oxide-polyacrylamide (GO-PAM) nanocomposite is evaluated for controlling the filtration properties, especially in a salty medium. First, GO nanosheets were functionalized, and then the GO-PAM nanocomposite was synthesized using the solution polymerization... 

Semiconductor-based photocatalysis is an efficient approach for degradation of organic pollutants. In this context, ZnO/g-C3N4 composite nanofibers containing carbonaceous species with different concentrations of g-C3N4 nanosheets (x = 0.25, 0.5, 1, 2, 10 wt%) noted as ZnO/carbon/(x wt%) g-C3N4 are prepared by electrospinning technique. For preparation of the composite nanofibers, bulk g-C3N4 is exfoliated to nanosheets, and then it is mixed with polyvinyl alcohol and appropriate zinc acetate content followed by electrospinning process. Thermal annealing of the as spun zinc acetate/poly(vinyl alcohol)/g-C3N4 nanosheets sample under N2 atmosphere leads to the formation of carbonaceous species... 

The development of a nonenzymatic glucose sensor working in real human body conditions through a noninvasive sampling approach has attracted considerable attention. Hence, this work focuses on the development of a new nonenzymatic glucose sensor based on flower-like Au nanostructures (F-AuNTs) and graphene oxide (GO) as a supporting matrix. The F-AuNTs-GO hybrid was synthesized by simple drop casting of the GO suspension onto the graphite sheet (GS) followed by electrodeposition of F-AuNTs on GO nanosheets at 3 V in a two-electrode system. The electrocatalytic activity of the F-AuNTs-GO/GS sensor toward glucose electrooxidation was initially evaluated in a 0.1 M buffer phosphate solution (pH... 

Engineering earth-rich, high-efficiency, and nonprecious electrocatalysts is an essential demand for water electrolysis to obtain clean and sustainable fuels. In this research, novel hybrid electrocatalysts based on coupling a hierarchical porous NiCo-mixed metal sulfide with a nanosheet structure (denoted as NiCoS) and a novel three-dimensional (3D) mesoporous open-cage/framelike structure of CoFeS are designed for oxygen evolution reaction (OER). In this regard, the single-step synthesis of a cobalt iron Prussian blue analog (CoFe PBA) frame/cagelike structure was performed without any etching step. Following a comparative study, CoFe PBA precursors were converted and doped with S, Se, and... 

Moving from two-dimensional hexagonal boron nitride (2D h-BN) flatlands towards their quantum sized zero-dimensional (0D) islands, as the newest member of the h-BN family, has recently opened up novel research areas due to the emergence of unique optical and physicochemical properties, excellent thermal and chemical stability, and desirable biocompatibility. This review elaborates on the fundamental properties of 2D and 0D h-BN nanomaterials and covers the latest progress in the fabrication and applications of BN nanosheets (BNNSs) and quantum dots (BNQDs). Initially, the transformation of properties in h-BN nanomaterials is discussed when moving from the 2D realm towards the 0D quantum... 

The potential of carbon-based nanosheet membranes with functionalized pores is great as water treatment membranes. Using the molecular dynamic simulation technique, the dimethyl sulfoxide (DMSO) separation from the water/DMSO binary solution is investigated, and the functionalized graphene nanosheets are used as a membrane. This membrane was functionalized by –F (fluorine) and –H (hydrogen) functional groups. For the separation of DMSO, external hydrostatic pressures up to 100 MPa were applied to the considered systems. The separation mechanism was based on molecular size. Multiple analyses were done to study the capability of considered membranes for the separation of DMSO molecules from...