Sharif Digital Repository

Herein, the effect of electrodeposition time on the super-capacitive performance of three-dimensional (3D) MnO2/g-C3N4 heterostructured electrodes was investigated. MnO2 nanoparticles were electrodeposited on the g-C3N4 nanosheets drop-casted on the Ni foam substrate. The microstructural analysis, carried out by FE-SEM and TEM, confirmed the homogeneous distribution of MnO2 nanoparticles on g-C3N4 nano-sheet layers. The electrochemical capacitive performances of the MnO2/g-C3N4 electrodes were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge tests, and electrochemical impedance spectra (EIS). The obtained results suggested that the supercapacitor (SC) performance of all... 

The increasing energy demand for next-generation portable and miniaturized electronics has drawn tremendous attention to develop microscale energy storage and conversion devices with light weight and flexible characteristics. Herein, we report the preparation of flower-like cobalt vanadium selenide/nickel copper selenide (CoVSe/NiCuSe) microspheres with three-dimensional hierarchical structure of micropore growth on copper wire for a flexible fiber microsupercapacitor (microSC) and overall water splitting. The CoV-LDH microspheres are anchored on the dendrite-like NiCu nanostructured Cu wire using a hydrothermal method (CoV-LDH/NiCu@CW). The sulfidation and selenization of CoV-LDH/NiCu was... 

The biodegradation behavior of Mg, coated by polymethyl methacrylate as well as polymethyl methacrylate (PMMA)−bioactive glass (BG) composite was investigated. Electrophoretic deposition and dip coating techniques were adopted to prepare composite coating using a suspension of different percentages of the above two chemical materials. The deposited coatings were characterized using SEM, EDS, FTIR, and water contact angle measurements. Biodegradation behavior study of the coated Mg was performed using linear polarization, impedance spectroscopy, and immersion tests in simulated body fluid. The compact and homogeneous composite coating was developed as evidenced by electron microscopy results.... 

High-performance photodetectors play critical roles in numerous photon-based applications in imaging, communication, and energy harvesting. Nowadays, heterostructures have received significant attention to extend the performance of photodetectors, with exceptionally high optical absorption and a wide absorption range. However, the enhancement factors, exact mechanism, and facile fabrication procedures are long-standing problems. Here, a heterojunction of a two-dimensional chemical vapor deposition-grown monolayer of WSe2with a Cu2ZnSnS4(CZTS) film is introduced. The CZTS film as an abundant material was synthesized in the form of nanoparticles, and it showed a great effect on the enhancement... 

Given the growing need for renewable energy and related technologies, researches have shifted to develop low-cost, stable, high-efficiency electrocatalysts in clean energy generation reactions such as water electrolysis. In the present paper, a three-dimensional Fe2TiO5/nitrogen-doped graphene (3D FTO/NG) nanocomposite is prepared using a simple, cheap and fast method, called chemical bath deposition (CBD). Structural and physical characterizations of the prepared electrocatalysts are performed by different methods such as Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform InfraRed spectra (FT-IR), Dynamic Light Scattering... 

We introduce an effective method for copper indium sulfide selenide (CISSe) doping with different alkali metals (Li, Na and K) based on a pre-deposited alkali chloride layer. A simple and fast spray method is used for pre-deposition of alkali chloride layer (LiCl, NaCl, KCl) on substrate surface before spray pyrolysis deposition of copper indium disulfide CuInS2 (CIS) films followed by selenization. The different properties of alkali-doped CISSe films by the alkali chloride pre-deposition (ACPD) method were compared to the post-deposition treatment (PDT) method. Based on FESEM images, a highly compact film with large grains can be obtained for CISSe films doped with K(∼0.72 μm) and Na (∼0.56... 

This research investigates the effect of process parameters on the geometry and properties of In625 parts, manufactured by the direct laser metal deposition (DLMD) process. For this purpose, eight parts, consisting of 5 layers on top of each other, were manufactured, and the effect of laser power, laser focal plane position, and scanning speed on the height, width, and surface smoothness of each of them was investigated using design of experiment (DOE). The experimental results showed that the height of the parts manufactured by 800 W/mm and 200 W/mm of energy density is 3.69 mm and 6.12 mm, respectively. The thickness of the parts manufactured by 80 W/mm and 200 W/mm of energy density is... 

Active edge sites of MoS2 nanosheets exhibit promising futures for hydrogen evolution reaction (HER), comparable with remarkable performances of highly cost platinum. However, 3D structures of MoS2 suffer from a lack of high mobility and unexposed active sites which lower the electrocatalytic activity. In this study, we show that there is a balance between increasing the active sites on the one hand and managing the charge transfer to facilitate the reaction on the other hand, and achieving this balance increases the efficiency of the electrocatalyst tremendously. For this purpose, we directly attached exfoliated MoS2 nanosheets onto carbon cloth (CC) substrate as a 3D network of conductive... 

Hybrid nanostructures and nanoarchitectures possess unique physicochemical properties such as high activity/functionality, enhanced physicochemical stability, and improved biocompatibility, which renders them suitable for various biomedical, pharmaceutical, environmental, and catalytic applications. In this context, core–shell nanophotocatalysts have shown superior activity compared to their counterparts, namely, their individual pristine semiconductors and composite materials components. Thus, the development of various innovative core–shell nanostructures as photocatalysts is of practical relevance in view of their unique properties with salient advantageous features applicable to, among... 

Synthesizing efficient electrode materials for water splitting and supercapacitors is essential for developing clean electrochemical energy conversion/storage devices. In the present work, we report the construction of a ruthenium cobalt oxide (RuCo2O4)/Ti3C2Tx MXene hybrid by electrophoretic deposition of Ti3C2Tx MXene on nickel foam (NF) followed by RuCo2O4 nanostructure growth through an electrodeposition process. Owing to the strong interactions between RuCo2O4 and Ti3C2Tx sheets, which are verified by density functional theory (DFT)-based simulations, RuCo2O4/Ti3C2Tx MXene@NF can serve as a bifunctional electrode for both water splitting and supercapacitor applications. This electrode... 

In order to make a Na–Y zeolite with Si/Al ratio of 2.27 more acidic with a higher volume of mesopores, a combination of different and consecutive methods including; chemical (i.e.; utilizing different compounds, such as NH4F and EDTA) and thermal/hydrothermal (i.e.; implementing calcination/steaming) methods, were employed for modification and dealumination. The combination of acidic-hydrothermal dealumination method led to a further structural collapse compared to that of the acidic calcination. In comparison with the other dealumination methods, the fluorination strategy (i.e.; utilizing NH4F) resulted in a zeolite with higher crystallinity, acidity, and specific surface area. The... 

Aperiodic perforated graphene layers were synthesized and used in fabrication of optical nanocavity absorbers. Chemical vapor deposition-grown graphene (Gr) layers were exposed to oxygen plasma etching to obtain the perforated graphene (pGr). The fabricated pGr/SiO2 (68 nm)/Ag (150 nm) nanocavity could present significant higher optical absorption, especially at around 530 nm wavelength region, as compared to a benchmark Gr/SiO2 (68 nm)/Ag (150 nm) sample. The effect of pore size of the pGr layer on the absorption property of the nanocavity has been studied by both experimental and numerical methods. The dependence of the absorption property of the nanocavity on the incident angles of... 

We present a procedure for simultaneous deposition of enzyme-laden chitosan/reduced graphene oxide (rGO) film by electrophoretic deposition (EPD) for fast and efficient detection of glucose. The role of rGO nanosheets is studied on the EPD kinetics of the enzyme-laden suspensions. Investigating the performance of the biosensor by electrochemical techniques indicates its high sensitivity (9700 μA.mM−1.cm−2), low limit of detection (4 µM), and suitable selectivity. © 2021 Elsevier B.V  

In this work, synthesis of CuIn0.75Ga0.25S2 (CIGS) nanoparticles, the formation of stable dispersion, deposition of high-quality films and, fabrication of thin-film Perovskite solar cells are reported. The stability of nanoparticle ink is crucial in the formation of device-quality films. The chalcogenide-based materials are widely used in thin-film solar cells; in particular, Cu(In,Ga)S2 are used as an absorber and hole transporting layer. In the present study, the nanoparticles of about 20 nm size and bandgap of 1.5 eV are synthesized using a heat-up method. A variety of solvents are used as dispersing media and the stability of the inks is evaluated by precise optical monitoring. We...