Ampicilina como inhibidor orgánico de la corrosión para los aceros AISI 1018 y AISI 8620

En este trabajo se presenta la evaluación de la ampicilina como inhibidor orgánico de la corrosión en los aceros AISI 1018 y AISI 8620, se resalta la importancia de la reutilización de los antibióticos caducados como inhibidores útiles para la disminución de la corrosión como una alternativa. Se utilizó la técnica de espectroscopia de impedancia electroquímica (EIS) para observar los cambios en la resistencia de polarización (Rp) en los aceros, los resultados de la EIS muestran que conforme se añade una mayor cantidad de inhibidor, la resistencia de polarización Rp aumenta y dado que la Rp se relaciona de manera inversa con la velocidad de corrosión esto significa que disminuye el proceso de corrosión.In this work the evaluation of ampicillin as an organic corrosion inhibitor for AISI 1018 and AISI 8620 steels is presented, the importance of the reuse of expired antibiotics as useful inhibitors for the diminution of corrosion as an alternative option is remarked. Electrochemical impedance spectroscopy (EIS) technique was used to observe changes on the polarization resistance (Rp) on the steels, EIS results show that as the amount of the inhibitor is increased the polarization resistance Rp increases and since Rp is inversely related with the corrosion rate therefore the corrosion process is decreased

Estudio de la reacción de oxidación de metanol a través de espectroscopia de impedancia electroquímica sobre NPs de Au@PtX/C con distintos planos preferenciales

En este trabajo se sintetizaron nanopartículas (NPs) del tipo núcleo envolvente soportadas en carbón Vulcan (Au@Pt/C, relación 1:1). Se utilizó iones de plata (Ag+) como agente modificador de forma, obteniéndose los catalizadores Au@Ptx/C (donde x es la relación atómica de Ag+ respecto a Pt, x=0,0.1 y 0.2). Los catalizadores se evaluaron en la reacción de oxidación de metanol (MOR) teniendo como sistema de referencia NPs de Pt/C esféricas. A través de STEM se observó que las NPs Pt y Au@Pt0 presentan una forma cuasi esférica, mientras que, las NPs [email protected] y [email protected] presentan formas poliédricas con la presencia de planos preferenciales (110). Se observó mediante voltamperometría cíclica que la MOR se favorece en el siguiente orden [email protected]/C> [email protected]/C> Au@Pt0/C> Pt/C, a través de la espectroscopia de impedancia electroquímica (EIS) se encontró que la forma de los espectros es función del potencial, así como del catalizador empleado, lo cual permite diferenciar distintos procesos que se llevan a cabo durante la MOR.In this work, core-shell type nanoparticles (NP) supported on carbon Vulcan (Au@Pt/C, 1: 1 ratio) were synthesized. Silver ions (Ag+) are used as a shape- modifying agent, obtaining Au@Ptx/C catalysts (where x is the atomic ratio of Ag+ respect to Pt, x = 0, 0.1 and 0.2). The catalysts were evaluated for the methanol oxidation reaction (MOR) using spherical Pt/C NPs as reference system. By using STEM, it was found that Pt and Au@Pt0 possess a quasi-spherical shape, while [email protected] and [email protected] NPs have polyhedral shape with the presence of preferential planes (110). By cyclic voltammetry, it was found that MOR is favored in the following order [email protected]/C>[email protected]/C>Au@Pt0/C>Pt/C, through electrochemical impedance spectroscopy (EIS ) it was found that shape of the spectra is a function of the potential, as well as the used catalyst, which allows differentiating different processes that are carried out during MOR

2’,6’diF2,4diBrDHBIQz como inhibidor de la corrosión del acero API X120

En el presente trabajo se hace un estudio sobre la eficiencia de inhibición de 2,4diBr2',6'diFDHBIQz 3 para la corrosión del acero API 5L X120 en una solución de HCI 0,5 M a 25ºC utilizando diferentes técnicas electroquímicas como, espectroscopía de impedancia electroquímica (EIS) y curvas de polarización (CP). Los resultados generales mostraron que 2',6'diF2,4diBrDHBIQz redujo significativamente la corrosión del aceroAPIX120 con una eficiencia de inhibición de aproximadamente 93% a una concentración de inhibidor de 150 ppm mediante espectroscopia de impedancia electroquímica.In the present work a study is made on the inhibition efficiency of 2,4diBr2',6'diFDHBIQz 3 for the corrosion of API 5L X120 steel in a solution of 0,5 M HCl at 25ºC using different electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and polarization curves (CP). Overall results showed that 2',6'diF2,4diBrDHBIQz significantly reduced corrosion of API X120 steel with an inhibition efficiency of approximately 93% at an inhibitor concentration of 150 ppm by electrochemical impedance spectroscopy

Evaluación electroquímica de dihidrobenzo [4,5] imidazo- [1,2c] quinazolinas para el control de la corrosión del acero API 5L X 120 en medio ácido

En el presente trabajo se determinó la eficiencia de inhibición para los compuestos orgánicos 2,6'diFDHBIQz 1 y 2Br2',6diFDHBIQz 2, para el control de la corrosión en un acero API SLX120 en un medio acido 0.5M HCI, usando técnicas electroquímicas como: Espectroscopía de impedancia electroquímica y curvas de polarización Potenciodinámicas, obteniendo una eficiencia del 94% a 200ppm en el inhibidor 1 (2',6'diFDHBIQz 1)y 93%a 100 y 150ppm en el inhibidor 2 (2Br2',6diFDHBIQz 2), a temperatura ambiente, después de realizar los ajustes con circuitos eléctricos equivalentes.In this paper the inhibition efficiency for organic compounds 2',6dFDHBIQz_1'diFDHBIQz_1 _and 2_Br2',6diFDHBIQz_2 diFDHBIQz_2 was determined for the control of corrosion in an API SL X120 steel in an acidic medium 0.5M HCI, using electrochemical techniques such as: Electrochemical impedance spectroscopy and polarization curves Potentiodynamics, obtaining an efficiency of 94% at 200ppm in inhibitor 1 (2,6diFDHBIQz 1) and 93% at 100 and 150ppm in inhibitor 2 (2Br2',6diFDHBIQz 2), at room temperature, after making adjustments with equivalent electrical circuits

Electrochemical Impedance Spectroscopy Analysis of 2-Mercaptobenzimidazole (2MBI) as Corrosion Inhibitor in HCl 1M

This work presents the results concerning the effect of different concentrations of an organic heterocyclic compound that displays corrosion inhibiting properties, known as 2-mercaptobenzimidazole, 2MBI, in a system comprising samples of the steel type API 5L X52 exposed to HCl 1M. The impedance spectra revealed that there was a continuous increase of |Z| as a function of increasing inhibitor concentrations in the electrolyte. A 200 ppm 2MBI was tested also, however, the greatest corrosion inhibiting efficiency was attained 99%, IE, with much smaller concentrations of the compound. This is sufficient reason to consider it a good corrosion inhibitor in HCl, just as it was effective for H 2 SO 4 . Furthermore, the inhibition kinetics study undertaken indicated that the 2MBI added in a fairly large concentration of 200 ppm in 1M HCl maintains its effectivity up to 32 immersion days. Also, it was observed that the corrosion potential, E corr , became more negative as the 2MBI organic molecules concentration increased in the system, which suggests that this inhibitor may be acting on the cathodic and anodic sites, thus being considered a mixed type inhibitor, in agreement with the corrosion mixed potential theory

Carbohidratos como inhibidores de la corrosión del acero API 5L X70 inmerso en medio ácido

Los carbohidratos comerciales D( + )-glucosa, D( + )galactosa y Metil α -D-glucopiranosa, así como los derivados de este último: Metil-4,6-O-Benciliden-a-D-glucopiranosa (MBG); Metoxi-2-Fenil- 7- (prop-2-yn-1-iloxi) Hexahidropirano[3,2-d][1,3]dioxin-8-0l (MFH); y Metil 4,6-O-benciliden-2-O-p-toluensulfonil- α -D-glucopiranosa (MBTG) fueron sintetizados y evaluados como inhibidores de la corrosión del acero API SL X70 inmerso en HCI 1M, en condiciones estáticas. La glucosa mostró mejor eficiencia como inhibidor de la corrosión, que la galactosa. De todos los carbohidratos evaluados el que demostró mejor eficiencia como inhibidor fue la Metil-4,6-O-Benciliden-α-D-glucopiranosa (MBG), siendo el menos eficiente el Metil α -D- glucosa.The commercial carbohydrates D (+) - glucose, galactose and Methyl-D-glucose, as well as the derivatives of the latter: Methyl-4,6-O-Benzylidene-α-D-glucopyranose (MBG); Methoxy-2- Phenyl- 7- (prop-2-yn-1-yloxy) Hexahydropyran [3,2-d] [1,3] dioxin-8-0l (MFH); and Methyl 4,6-O-benzylidene-2-Op- Toluenesulfonyl-α-D-glucopyranose (MBTG) were synthesized and evaluated as corrosion inhibitors of API SL X70 steel immersed in 1M HCl, under static conditions. Glucose was a better inhibitor of corrosion than galactose. Of all the carbohydrates evaluated, the best of all was Methyl-4,6-O-Benzylidene- α-D¬glucopyranose (MBG), with Methyl-D-glucose being the least efficient

Cálculo del coeficiente de difusión del Zn en un disolvente eutéctico profundo mediante técnicas electroquímicas

En el presente trabajo se llevó a cabo la determinación electroquímica del coeficiente de difusión del Zn²⁺, en un disolvente eutéctico profundo compuesto por cloruro de colina y urea, en una relación molar de 1:2, a una temperatura de 70 °C. Para ello se emplearon las técnicas electroquímicas de voltamperometría cíclica y cronoamperometría. A partir de los transitorios potenciostáticos de corriente, de la ecuación de Cottrell y mediante el análisis de las coordenadas del máximo, se calculó el valor para D= 4.76x10-⁸ cm²s-¹ y D= 6.71x10-⁸ cm²s-¹, respectivamente.In the present work it was carried out the electrochemical determination of the diffusion coefficient of Zn²⁺, in a deep eutectic solvent composed of choline chloride and urea in a molar ratio of 1:2, at a temperature of 70°C. For this, the electrochemical techniques of cyclic voltammetry and chronoamperometry were used. From potentiostatic current transients and Cottrell equation, the value for D=4.76x10-⁸ cm²s-¹ and D=4.76x10-⁸ cm²s-¹ was calculated, respectively

Cuantificación electroquímica de la superficie electroactiva de nanopartículas de Au soportadas sobre ITO a diferentes monocapas mediante electrodepósito de Cu a subpotencial

En el presente trabajo, se llevó a cabo la determinación del área superficial activa, ASA, de nanopartículas de Au, AuNPs, soportadas sobre ITO, a diferentes monocapas de AuNPs. Para llevar a cabo lo anterior, se formaron monocapas de AuNPs sobre la superficie del electrodo de ITO a través de un policatión, la poli L-lisina, PLL, entre cada capa. Una vez formada cada monocapa, se lleva a cabo el proceso de electrodepósito de Cu a subpotencial, UPD, en una disolución acuosa de Cu²⁺, empleando las técnicas electroquímicas de voltamperometría cíclica y cronoamperometría. Del análisis de los transitorios potenciostáticos de corriente se determinó la carga eléctrica involucrada en el proceso de formación de cada monocapa, y a partir de esta se determinó el ASA con respecto a las monocapas 1, 2 y 5.The present work was conducted to determine the active surface area, ASA, of Au nanoparticles, AuNPs, supported on ITO, to different monolayers AuNPs. To perform the above, AuNPs monolayers on the surface of ITO electrode is formed through a polycation, poly L-lysine, PLL, between each layer. Each monolayer once formed, is held the Cu electroplating process underpotential, UPD, in an aqueous solution of Cu²⁺, using electrochemical techniques such as cyclic voltammetry and chronoamperometry. Analysis potentiostatic current transient electrical load involved in the formation of each monolayer was determined, and from this, the ASA was determined over monolayers 1, 2 and 5

Photoelectron Spectroscopy at the Graphene-Liquid Interface Reveals the Electronic Structure of an Electrodeposited Cobalt/Graphene Electrocatalyst.

Electrochemically grown cobalt on graphene exhibits exceptional performance as a catalyst for the oxygen evolution reaction (OER) and provides the possibility of controlling the morphology and the chemical properties during deposition. However, the detailed atomic structure of this hybrid material is not well understood. To elucidate the Co/graphene electronic structure, we have developed a flow cell closed by a graphene membrane that provides electronic and chemical information on the active surfaces under atmospheric pressure and in the presence of liquids by means of X-ray photoelectron spectroscopy (XPS). We found that cobalt is anchored on graphene via carbonyl-like species, namely Co(CO)x , promoting the reduction of Co(3+) to Co(2+), which is believed to be the active site of the catalyst.HZB is acknowledged for granting beamtime at the ISSIS endstation under proposal #14201159. This work was funded from EU project GRAFOL grant 285275 and by SYNESTESia project grant 05K14EWA (BMBF). R.S.W. acknowledges a Research Fellowship from St. John’s College, Cambridge and a Marie Skłodowska-Curie Individual Fellowship (Global) under grant ARTIST (no. 656870) from the European Union’s Horizon 2020 research and innovation programme.. C.H.C. acknowledges financial support from projects 103-2112-M-032-004 and 102-2632-M-032-001 -MY3. M.S. was supported by the Office of Science, Division of Materials Sciences and Engineering, of the U.S. Department of Energy (DOE) under Contract No. DEAC02-05CH11231.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/anie.20150604