Ali Ehsani

Electrochemical and DFT study on the inhibition of 316L stainless steel corrosion in acidic medium by 1-(4-nitrophenyl)-5-amino-1H-tetrazole

1-(4-nitrophenyl)-5-amino-1H-tetrazole was synthesized and its inhibiting action on the corrosion of 316L stainless steel (SS) in sulfuric acid was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). In the potentiodynamic polarization measurements the values of βc had small changes with increasing inhibitor concentration, which indicated that the 1-(4-nitrophenyl)-5-amino-1H-tetrazole was adsorbed on the metal surface and the addition of the inhibitor hindered the acid attack on the SS electrode. The shift in the anodic Tafel slope βa might be attributed to the modification of the anodic dissolution process due to the inhibitor module adsorption on the active sites. The results of the investigation show that the newly synthesized compound shows excellent inhibition efficiencies against the corrosion of SS in acidic solution. The adsorption of 1-(4-nitrophenyl)-5-amino-1H-tetrazole onto the SS surface followed the Langmuir adsorption model with the free energy of adsorption ΔG0ads of −9.44 kJ mol−1. Quantum chemical calculations were employed to give further insight into the mechanism of inhibition action of 1-(4-nitrophenyl)-5-amino-1H-tetrazole.

Ultrasound-promoted green approach for the synthesis of sulfonamides using natural, stable and reusable Natrolite nanozeolite catalyst at room temperature

Natural Natrolite nanozeolite has been investigated as an efficient and reusable catalyst for the N-sulfonylation of amines under ultrasound irradiation at room temperature. Compared with traditional methods, the significant advantages for method are green solvent, milder and cleaner conditions, higher purity and yields, shorter reaction time, easier work-up procedure and the lower generation of waste or pollutions. The catalyst can be recovered and reused several times without significant loss of its catalytic activity.

Facile electrosynthesis of nano flower like metal-organic framework and its nanocomposite with conjugated polymer as a novel and hybrid electrode material for highly capacitive pseudocapacitors

The [Cu(btec)0.5DMF] (H4btec=1,2,4,5-benzenetetracarboxylate acid) was electrosynthesized on the graphite working electrode by applying catholic potential. The [Cu(btec)0.5DMF] grows on a graphite surface which results from the coordination of 1,2,4,5-benzenetetracarboxylate anions with Cu2+ cations. The electrosynthesized [Cu(btec)0.5DMF] was characterized by X-ray diffraction, scanning electron microscopy. Furthermore, POAP/Cu(btec)0.5DMF nanocomposite film electrosynthesized on the surface of the carbon paste electrode by cyclic voltammetry. Different electrochemical methods including galvanostatic charge-discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy are carried out in order to investigate the performance of the system. This work introduces new nanocomposite materials for electrochemical redox capacitors with advantages including ease synthesis, high active surface area and stability in an aqueous electrolyte.

Synthesis and highly efficient supercapacitor behavior of a novel poly pyrrole/ceramic oxide nanocomposite film

A novel electrochemical synthetic method for yttrium aluminum garnet (YAG:Al5Y3O12) was successfully developed in a mixture of YCl3 and AlCl3 aqueous solution. The electrosynthesized YAG was further annealed and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). A Ppy/YAG thin film electrode was synthesized electrochemically as an electrochemical supercapacitor. Scanning electron micrographs clearly reveal the formation of nanocomposites on the surface of the working electrode. Different electrochemical techniques, including galvanostatic charge–discharge (CD) experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), were used to investigate the applicability of the system as a supercapacitor. Based on the electrochemical results obtained, Ppy/YAG gave higher specific capacitance, power and energy values than Ppy at a current density of 1 mA cm−2. The specific capacitance (SC) of the Ppy and Ppy/YAG electrodes was calculated using the CV method, which was 109 and 254 F g−1, respectively. This study introduces new nanocomposite materials for electrochemical redox capacitors, which have advantages, such as long life cycle and stability in an aqueous electrolyte, to that of the commonly used ruthenium based perovskites.

Nanocomposite of p-type conductive polymer/functionalized graphene oxide nanosheets as novel and hybrid electrodes for highly capacitive pseudocapacitors.

An effective approach for increasing the life cycle of poly ortho aminophenol (POAP) as a p-type conductive polymers is combining conventional conductive polymers and nanomaterials to fabricate hybrid electrodes. In this paper, functionalized graphene oxide (FGO) has first been synthesized using a chemical approach. Hybrid POAP/FGO films have then been fabricated by POAP electropolymerization in the presence of FGO nanoparticles as active electrodes for electrochemical supercapacitors. Based on the atomic scale study results, it seems that H3PO4(-) oxygen atoms and terminal pyridine ring nitrogen atoms play a crucial role in the intramolecular charge and energy transfer in the FGO molecular systems. Theoretical studies, surface and electrochemical analyses have been used for characterization of POAP/FGO composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. This work introduces new nanocomposite materials for electrochemical redox capacitors with such advantages as the ease of synthesis, high active surface area and stability in an aqueous electrolyte.

Palladium on nano-magnetite: a magnetically reusable catalyst in the ligand- and copper-free Sonogashira and Stille cross-coupling reactions

This paper reports on the synthesis and use of palladium on nano-magnetite as a magnetically separable catalyst for copper- and ligand-free Songashira and Stille coupling reactions. The catalyst was characterized using powder XRD, SEM, EDS and VSM techniques. This method has the advantages of high yields, simple methodology and easy work-up. Catalytic efficiency remains unaltered even after several repeated cycles.

A simple and innovative route to electrosynthesis of Eu2O3 nanoparticles and its nanocomposite with p-type conductive polymer: Characterisation and electrochemical properties.

Conductive polymers are usually used as an electrode in redox supercapacitor. However, due to accumulation of stress on polymer during repeating charge-discharge process, the cycle life of pure conductive polymer is poor, which needs to be further improved. For this purpose, combining conventional conductive polymers active material and nanomaterials to fabricate hybrid electrode has been considered to be one of the efficient avenues. In this paper, a simple and rapid electrochemical method has been carried out to prepare Eu2O3 nanoparticles and hybrid POAP/Eu2O3 to serve as the active electrode for electrochemical supercapacitor. Structural and morphological characterisations of Eu2O3 and composite film were carried out using powder X-ray diffraction, field emission scanning electron microscopy and energy dispersion of X-rays. Their electrochemical properties were also investigated using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The as-prepared composites had excellent properties in the specific capacitance and a coulombic efficiency of 95%. The as-prepared composites had excellent properties in the capacitance, and its specific capacitance was up to 375Fg(-1) and a coulombic efficiency of 95%. This work introduces new nanocomposite materials for electrochemical redox capacitors with advantages including ease synthesis, high active surface area and stability in an aqueous electrolyte.

Physioelectrochemical investigation of the supercapacitive performance of a ternary nanocomposite by common electrochemical methods and fast Fourier transform voltammetry

Ternary nanocomposite materials of polyaniline, as supercapacitor electrodes with remarkably high specific capacitance, are electrosynthesized on a glassy carbon electrode (GCE). Scanning electron micrographs clearly revealed the formation of the nanocomposites on the surface of the working electrode. The supercapacitor properties of the composite films are investigated by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge/discharge and fast Fourier transform continuous cyclic voltammetry (FFTCCV) technique in an acidic solution. A very high specific capacitance of 303 F g−1 is obtained from PANI in the presence of reduced graphene oxide and Au nanoparticles in an acidic electrolyte. Furthermore, the FFTCCV technique is considered as the most powerful technique in the characterization of new composite materials for supercapacitors. By using this technique, the electrochemical behavior of the system is monitored momentarily. The absolute capacitive charge changes (ΔQn) are calculated from the three-dimensional (3D) CVs of the composite electrode at a scan rate of 50 mV s−1 and a computer program algorithm. The present study introduces new nanocomposite materials for electrochemical redox capacitors with advantages that include long life cycling and stability due to the synergistic effects of each component.

Green synthesis, optical properties and catalytic activity of silver nanoparticles in the synthesis of N-monosubstituted ureas in water

We report the green synthesis of silver nanoparticles by using Euphorbia condylocarpa M. bieb root extract for the synthesis of N-monosubstituted ureas in water. UV-visible studies show the absorption band at 420 nm due to surface plasmon resonance (SPR) of the silver nanoparticles. This reveals the reduction of silver ions (Ag+) to silver (Ago) which indicates the formation of silver nanoparticles (Ag NPs). This method has the advantages of high yields, simple methodology and easy work up.

Facile and surfactant-free synthesis of Pd nanoparticles by the extract of the fruits of Piper longum and their catalytic performance for the Sonogashira coupling reaction in water under ligand- and copper-free conditions

This work reports a facile synthesis of palladium nanoparticles (Pd NPs) by the extract of the fruits of Piper longum without any stabilizer or surfactant. The Pd NPs were found to be effective catalysts for the ligand-, amine- and copper-free Sonogashira coupling reaction under aerobic conditions. The Pd NPs were characterized with UV-vis, FT-IR and TEM methods. This method has the advantages of high yields, simple methodology, and elimination of ligands, copper, organic solvents and homogeneous catalysts and easy work up. Water is used as the only solvent for the coupling reaction. More importantly, the catalyst was recovered and recycled by a simple decantation of the reaction solution and used for five consecutive trials without significant loss of its reactivity.