Electrodeposition of Epitaxial Magnetite Films and Ferrihydrite Nanoribbons on Single-Crystal Gold

Abstract

Magnetite (Fe3O4), ferrihydrite (Fe10O14(OH)2), and iron (Fe) films were electrodeposited by cathodic deposition from an alkaline Fe(III)−triethanolamine solution. The electrodeposited phase depended on the applied potential. Magnetite films were electrodeposited from −1.01 to −1.10 V vs Ag/AgCl, whereas ferrihydrite films were deposited from −1.10 to −1.20 V vs Ag/AgCl. Iron deposition occurred at more negative potentials. The polycrystalline films were characterized using X-ray diffraction, scanning electron microscopy, and Mössbauer spectroscopy. Epitaxial magnetite films on low-index gold crystals were produced at three different potentials. X-ray diffraction analysis of the magnetite films deposited at −1.01, −1.05, and −1.10 V vs Ag/AgCl showed [111] oriented films on Au(111) and Au(001). Because of twinning of the {111} planes, the [511] orientation was present in thicker films. Magnetite grew with a [110] orientation on Au(110). At the more negative potentials of −1.10 and −1.20 V vs Ag/AgCl, ferrihydrite deposited with an (112̅0) orientation.

Corrosion Behavior of Alloy 600 Coupled with Electrodeposited Magnetite in Simulated Secondary Water of PWRs

“…16,18) On the contrary, the second reduction wave between ¹1.20 and ¹1.30 V SCE seems to be due to a two-electron process corresponding to the reduction of Fe(II) to Fe.…”

Electrodeposition of Magnetite on Carbon Steel in Fe(III)-Triethanolamine Solution and Its Corrosion Behavior

“…(1). 12,13) During the initial stage of electrodeposition at ¹1.05 V SCE , increase of the surface area by deposition of magnetite slightly increased the cathodic current density due to the increase of the current. Between ¹1.25 and ¹1.30 V SCE , a two-electron process shows the reduction of Fe(II) to Fe then for more negative potential the increase of the cathodic current density was due to hydrogen gas evolution corresponding to eq.…”

“…This corrosion product reduces the efficiency of the steam generator by deterioration of the heat transfer and cause an acceleration of the corrosion of steam generator tube. 13) Hence, its removal improves heat transfer and reduces localized corrosion. 1) Some authors recently presented that the magnetite accelerates the corrosion of the carbon steel by a galvanic coupling.…”

Epitaxial Electrodeposition of Chiral Films Using Chiral Precursors

“…In this process, the electrochemically produced species reacts with water or hydroxide ions to form a metal oxide on the electrode. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] A second method to produce thin films is to electrochemically change the pH of the electrolyte at the electrode surface. Because the solubility of any material is dependent on pH, the pH can be electrochemically changed at the electrode surface, thus lowering the solubility of the material and resulting in the precipitation of the material only on the electrode surface.…”

“…Once the nucleation layer is produced, the film maintains the orientation regardless of the precursor. [47] Studies on adsorption of organic molecules on surfaces have shown that local chiral imprinting can be obtained without the need of extended surface Chirality. [6] Adsorption of amino acids on Au [66] and Ag [67] surfaces are reported to be physical in nature, while amino acids chemisorb on Cu single crystals.…”