Synergistic effect p-phenylenediamine and n,n diphenylthiourea on the electrochemical corrosion behaviour of mild steel in dilute acid media

Electrochemical studies of the synergistic effect of p-phenylenediamine and n,n diphenylthiourea (TPD) as corrosion inhibitor of mild steel in dilute sulphuric and hydrochloric acid through weight loss and potentiodynamic polarization at ambient temperature were performed. Experimental results showed the excellent performance of TPD with an optimal inhibition efficiency of 88.18 and 93.88 %in sulphuric and 87.42 and 87.15 %in hydrochloric acid from both tests at all concentration studied. Polarization studies show the compound to be a mixed-type inhibitor. Adsorption of deanol on the steel surface was observed to obey the Langmuir and Frumkin isotherm models. X-ray diffractometry confirmed the absence of corrosion products and complexes. Optical microscopy confirmed the selective inhibition property of TPD to be through chemical adsorption on the steel surfac

A novel, effective and low cost electrocatalyst for direct methanol fuel cells applications

Electrocatalytic oxidation of methanol in alkaline solution on a NiCd/C catalyst chemically modified by a leaching process of Zn was investigated. Scanning electron microscopy (SEM), X-ray florescence spectroscopy (XRF) and atomic force microscopy (AFM) were used for coating characterization. The electrochemical properties and behaviors and also kinetic values of alkaline leached NiCdZn/C catalyst were characterized using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The electrocatalytic activity of The alkaline leached NiCdZn/C catalyst toward methanol oxidation is shown to strongly depend on The porous and larger structure of coating and increasing of electrocatalytic active sites. The prepared catalyst in The present work is The most promising system for use in direct methanol fuel cells. © 2015 Hydrogen Energy Publications, LLC.FEF2010D7This study has been financially supported by the Çukurova University Research Fund (Project Number: FEF2010D7 ). The authors are greatly thankful to Çukurova University research fund

Electrocatalysis of Ni-promoted Cd coated graphite toward methanol oxidation in alkaline medium

The nickel-cadmium (Ni-promoted Cd) catalyst for using direct methanol fuel cell (DMFC) applications is electrochemically deposited on a graphite substrate. The activity of methanol oxidation is assessed by recording cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. The surface morphologies and chemical compositions of catalysts are determined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray florescence spectroscopy (XRF). Mean roughness of catalysts is measured by atomic force microscopy (AFM). Kinetic parameters of oxidation such as the anodic electron transfer coefficient (? a) , cathodic electron transfer coefficient (? c) and charge transfer rate constant (k s) are calculated. The effect of methanol concentration and temperature on methanol oxidation is also investigated. The electrochemical measurements show that the addition of Cd to single coating enhances the electrocatalytic properties for methanol oxidation and Ni-promoted Cd/C has the best catalytic activity and stability. © 2012 Elsevier B.V. All rights reserved.FEF2010D7This study has been financially supported by the Çukurova University research fund (Project Number: FEF2010D7). The authors are greatly thankful to Çukurova University research fund

Preparation, characterization and application of alkaline leached CuNiZn ternary coatings for long-term electrolysis in alkaline solution

The NiCuZn ternary coating was electrochemically deposited on a copper electrode. Then, it was etched in a concentrated alkaline solution (30% NaOH) to produce a porous and electrocatalytic surface suitable for use in the hydrogen evolution reaction (HER). The surface composition of coating before and after alkaline leaching was determined by energy dispersive X-ray (EDX) analysis. The surface morphologies were investigated by scanning electron microscopy (SEM). The long-term stability of electrode prepared for alkaline water electrolysis was investigated in 1 M KOH solution with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that, the NiCuZn coating has a compact and porous structure with good physical stability. Alkaline leaching process further improved the activity of NiCuZn coating in comparison with binary NiCu deposit for the HER. The long-term operation at -100 mA cm-2 showed good electrochemical stability over 120 h. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.FEF2006D8 106T542The authors are greatly thankful to Çukurova University research fund (Project Number: FEF2006D8 ) and TUBITAK (Project Number: 106T542 ) for financial support

Inhibition effect of rhodanine-N-acetic acid on copper corrosion in acidic media

The inhibition effect of Rhodanine-N-acetic acid (R-NA) on copper corrosion in acidic media is studied by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization resistance (LPR). The surface morphology is investigated by using scanning electron microscopy (SEM). The exposure of copper surface to 0.5 M H2SO 4 solution in short and long immersion times in the absence and presence of the inhibitor is also examined. The results show that R-NA is a powerful inhibitor for copper corrosion in acidic media due to its strong adsorption onto the metal surface. Moreover our results are compared with similar compounds in the literature. © 2013 American Chemical Society

NiMn composite electrodes as cathode material for hydrogen evolution reaction in alkaline solution

NiMn composite catalysts (C/NiMn, C/NiMnZn, C/NiMnZn-PtRu and C/NiMnZn-PtPd) have been prepared on the graphite substrate (C) by electrochemical deposition as electrocatalytic materials for hydrogen evolution reaction (HER). The NiMnZn coatings were etched in a concentrated alkaline solution (30% NaOH) to produce a porous and electrocatalytic surface suitable for the HER. After the leaching process, a low amount of binary PtPd and PtRu were deposited onto the etched NiMnZn deposit in order to improve the catalytic activity for the HER. Surface morphology and composition of the catalysts were analyzed by scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX). © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.FEF2011BAP12The authors are greatly thankful to Çukurova University Research Fund for financial support (Project Number: FEF2011BAP12)

Electrocatalytic behavior of the Pd-modified electrocatalyst for hydrogen evolution

The hydrogen evolution behavior of C/CoSn, C/CoSnZn and C/CoSnZn-Pd catalysts which were prepared on a graphite substrate (C) by electrochemical deposition, as well as their electrochemical properties in the KOH solutions, have been investigated by the polarization measurements, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and electrolysis techniques. C/CoSnZn catalyst was etched in caustic to leach out zinc and to produce the Raney-type, porous electrocatalytic surface for hydrogen evolution. In order to further improve the catalytic activity of the C/CoSnZn catalyst for the hydrogen evolution reaction (HER), this catalyst was modified by loading a small amount of Pd. Results showed that the modification of C/CoSnZn catalyst by deposition of a small amount of Pd can render cathode material very active in hydrogen evolution. High catalytic activity of the C/CoSnZn-Pd catalyst depends on the surface porosity, large specific surface area and well known intrinsic catalytic activity of Pd. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.This study has been financially supported by the Çukurova University research fund. The authors are greatly thankful to Çukurova University research fund

The stability of hydrogen evolution activity and corrosion behavior of NiCu coatings with long-term electrolysis in alkaline solution

In this study, NiCu composite coating was electrochemically deposited on a copper electrode (Cu/NiCu) and tested for hydrogen evolution reaction (HER) in 1 M KOH solution for long-term electrolysis with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. The bulk and surface composition of the coating was determined using atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analysis. The surface morphology was investigated by scanning electron microscopy (SEM). The effect of electrolysis on the corrosion behavior of the Cu/NiCu electrode was also reported. It was found that the NiCu coating had a compact and porous structure with good time stability. The HER activity of the coating was stable over 120 h electrolysis and the HER mechanism was not modified during the operation. The corrosion tests showed that the corrosion resistance of the Cu/NiCu electrode changed when a cathodic current was applied to the electrolysis system. © 2009 International Association for Hydrogen Energy.106T542 FEF2006D8This study has been financially supported by Cukurova University research fund (Project Number: FEF2006D8) and The Scientific and Technical Research Council of Turkey (TUBITAK) (Project Number: 106T542). The authors are greatly thankful to Cukurova University research fund and TUBITAK for financial support