Sharif Digital Repository

A novel approach named a magnetic flowable electrode (MFE) is proposed for the first time to enable enhancement of redox flow batteries (RFBs) performance. This approach enables the formation of a high active surface area electrode from magnetic nanomaterials, without the need to fabricate a self-supporting three-dimensional electrode structure. To form a simple MFE, magnetic modified carbon nanotubes are dispersed in the electrolyte, and permanent magnets are embedded behind the current feeder to apply a magnetic field across the flow cell channels. With circulating electrolyte, magnetic carbon nanotubes are aggregated on the graphite bipolar plate to form a well-structured nanoscale... 

For the first time graphene nanosheets and carbon nanospheres/chitosan (GNS-CNS/CS) based nanocomposite film modified electrode was used for the electro-oxidation of mebendazole (MD). MD is a benzimidazole drug that is used to treat human infections caused by parasitic worms. MD causes slow immobilization and death of the worms by selectively and irreversibly blocking uptake of glucose. The electrochemical behavior of MD at GNS-CNS/CS modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry in aqueous media at different pHs. The prepared electrode showed an excellent electrochemical activity toward the electro-oxidation of MD leading to a... 

Porous network-like MnO2 thick films are successfully synthesized on a flexible stainless steel (SS) mesh using a simple and low-cost electrodeposition method followed by an electrochemical activation process. Morphology, chemical composition, and crystal structure of the prepared electrodes before and after the activation process are determined and compared by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analyses. The results show that the implementation of the electrochemical activation process does not change the chemical composition and crystal structure of the films, but it influences the surface morphology of the MnO2... 

The present work describes the preparation and electrochemical characterization of RuO2/MWCNT/Stainless Steel Mesh (SSM) electrode as compared with a MWCNT/SSM electrode in the positive half-cell of a Vanadium Redox Flow Battery (VRFB). The electrochemical characterization of prepared electrode was carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge procedures. The electrochemical activity of MWCNT/SSM modified with RuO2 as positive electrode in a VRFB was notably improved. The RuO2-included electrodes demonstrated high peak current ratio, small peak potential difference and high electron... 

Abstract: The electrodeposition of platinum nanoparticles (PtNPs) on multiwall carbon nanotubes (MWCNTs)/fluorine-doped tin oxide glass (FTO) was investigated. Nucleation and growth mechanisms were studied via Scharifker and Hills model. Chronoamperometry results clearly show that the electrodeposition processes are diffusion-controlled and the diffusion coefficient is 1.5×10-5cm2/s. The semi-spherical particles with lamellar morphology were observed in 1M H 2SO 4, while a petal shape was discerned in 0.5M H 2SO 4. Also, dispersion, size, and uniformity of PtNPs were investigated, where the finer distribution of PtNPs with the average size less than 100 nm was obtained in 0.5M H 2SO 4... 

Electrochemical activity of TiO2 nanotube arrays (NTAs) is restricted by a wide band gap of TiO2. To overcome this restriction, we considered systematic research on two effective methods of doping of TiO2 NTAs such as the N-doping and electrochemical reductive doping and predicting the proper application of them. Band gap narrowing was occurred from 3.16 eV for undoped TiO2 NTAs to 2.9 and 2.7 eV at N-doped and self-doped TiO2 ones respectively. The electrochemical responses of the TiO2 NTAs before and after doping were examined by cyclic Voltammetry (CV) curve. To understand the electrochemical behavior of the undoped and doped TiO2 NTAs, electrochemical impedance spectroscopy (EIS) was... 

Thin carbon nanoparticle/Nafion film (CNP/N), as a novel electrode material, is formed on the surface of the glassy carbon electrode in a simple solvent evaporation process. The electrochemical behavior of Azathioprine (Aza) at the CNP/N-modified electrode is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of Aza, an irreversible cathodic peak is appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a four-electron process referring to the reduction of nitro group to the corresponding hydroxylamine. The prepared electrode showed... 

This work presents a novel melatonin sensor based on unfunctionalized macroporous graphene networks decorated with gold nanoparticles for the differential pulse voltammetric detection of melatonin in pharmaceutical products. Highly porous graphene structures were prepared by metallic template-assisted chemical vapor deposition, and their active surface area and electrocatalytic activity were improved by electrochemical deposition of gold nanoparticles (50-250 nm) on their struts. The graphene-gold electrodes present a highly sensitive performance toward electro-oxidation of melatonin with a wide linear range of 0.05-50 μM, a low detection limit of 0.0082 μM (3σ/m), and a significant... 

In this research, the ZnOG hybrid thin film was produced via solgel method. The surface morphology, band gap and photoactive properties of the films were studied by means of SEM, UV–Vis and photoluminescence analysis. In addition, the ability of the thin film in photocathodic protection of carbon steel (CS) and 304 stainless steel in 3.5 wt.% NaCl and Na2S solutions under dark and UV illumination was investigated by polarization test as well as OCP and current measurements during coupling of steels with ZnOG photoanode. The mix band gap is reduced to the orders of 1.17 eV through hybridization of ZnO with graphene oxide. In both NaCl and Na2S solutions, the ZnOG thin film could effectively... 

The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to... 

The electrochemical behavior of lamotrigine (LMT) at the pyrolytic graphite electrode (PGE) is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of LMT, an irreversible cathodic peak appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a two-electron process referring to the reduction of azo group. The electrode showed an excellent electrochemical activity toward the electro-reduction of LMT, leading to a significant improvement in sensitivity as compared to the glassy carbon electrode. The results of electrochemical impedance...