AppliedChem

17 pages, 7847 KiB

Open AccessArticle

Electrochemical Analysis of Corrosion Resistance of Manganese-Coated Annealed Steel: Chronoamperometric and Voltammetric Study

by Francisco Augusto Nuñez Pérez

AppliedChem 2024, 4(4), 367-383; https://doi.org/10.3390/appliedchem4040023 - 19 Nov 2024

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Abstract

Metal corrosion poses a significant challenge for industries by decreasing the lifespan of materials and escalating maintenance and replacement costs. This study is critically important, as it assesses the corrosion resistance properties of annealed steel wire electrodes coated with manganese, employing chronoamperometry and linear voltammetry techniques. The electrodes were immersed in an electrolyte solution and subjected to chronoamperometry at various voltages (−0.55 V, −0.60 V, and −0.70 V) and durations (60 s and 1800 s). Subsequently, linear voltammetry was performed over a potential range from −0.8 V to 0.8 V to generate Tafel plots. The Butler–Volmer equation was applied to the data obtained to determine the corrosion current density. The results indicate that the optimal conditions for forming a highly effective protective manganese layer occur at a potential of −0.70 V for 1800 s. Under these conditions, the electrodes exhibited superior corrosion resistance. This study also revealed that shorter durations and less negative potentials led to less-effective manganese coatings, with higher corrosion rates and reduced stability. These findings are significant for developing efficient corrosion protection methods in industrial and research applications, providing clear parameters for optimizing the manganese electrodeposition process on annealed steel. Full article

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14 pages, 8292 KiB

Open AccessArticle

Synthesis and Electrochemical Characterization of Ru-Modified Iridium Oxide Catalysts for PEM Electrolysis

by Stanford Chidziva, Dorcas Zide, Joshua John Bambo, Anele Sinto, Sivakumar Pasupathi and Bernard J. Bladergroen

AppliedChem 2024, 4(4), 353-366; https://doi.org/10.3390/appliedchem4040022 - 24 Oct 2024

Viewed by 838

Abstract

In the search of sustainable energy solutions, proton exchange membrane water electrolyzers (PEMWEs) have emerged as a promising alternative for sustainable clean hydrogen production. This study focuses on synthesis and characterization of Ruthenium (Ru)-modified iridium oxide (IrO₂) catalysts. The anode is the principal reason for the high overpotential of PEMWEs and it also greatly increases the cost of the electrolyzers. IrO₂ is highly stable and corrosion-resistant, particularly in acidic environments, making it a durable catalyst for the oxygen evolution reaction (OER) in PEMWEs, though it suffers from a relatively high overpotential. Ruthenium oxide (RuO₂), on the other hand, is more catalytically active with a lower overpotential, but is less stable under the same conditions. In this study, the goal was to improve the catalytic activity and stability of the anode catalyst, IrO₂, through the controlled incorporation of Ru and to reduce overall catalyst cost due to the reduced iridium content. This synergistic combination allows for better performance in terms of conductivity, efficiency, and durability, making Ru-modified IrO₂ an ideal catalyst for OER in PEMWE applications. The Adams fusion method was adapted and used to synthesize the catalysts. The modified catalysts were characterized using analytical instruments. These analyses provided insights into the structural, morphological, and electrochemical properties of the Ru-modified IrO₂ catalysts. Full article

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20 pages, 1346 KiB

Open AccessArticle

Group Contribution Revisited: The Enthalpy of Formation of Organic Compounds with “Chemical Accuracy” Part VI

by Robert J. Meier and Paul R. Rablen

AppliedChem 2024, 4(4), 333-352; https://doi.org/10.3390/appliedchem4040021 - 23 Oct 2024

Viewed by 576

Abstract

In this paper we provide the reader with a ready to use Group Contribution (GC) method for the heat of formation (gaseous state) of organics in the form of an Excel spreadsheet with all data, enabling further predictions, and an accompanying manual on how to use the GC model for predicting the heat of formation for organics. In addition, in order to widen the applicability of the method whilst retaining chemical accuracy compared to our previous publications on this topic, we include further chemical groups including acetals, benzyl ethers, bicyclic hydrocarbons, alkanediols and glycerol, polycyclic aromatic hydrocarbons, aromatic fluoro compounds, and finally several species which we include to illustrate how the GC model can be successfully applied to species we did not consider during the parameterization of the GC model parameters. Full article

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13 pages, 7488 KiB

Open AccessArticle

Molecular Docking Assessment of Limonoids from Cameroonian Entandrophragma Species as Potential Inhibitors of Anopheles gambiae Acetylcholinesterase (AChE)

by Gervais Mouthé Happi, Sajjad Haider, Sikiru Akinyeye Ahmed and Zaheer Ul-Haq

AppliedChem 2024, 4(4), 320-332; https://doi.org/10.3390/appliedchem4040020 - 22 Oct 2024

Viewed by 628

Abstract

Malaria remains one of the great killers in tropical regions of the world due to the transmission of the Plasmodium parasite by the bites of the female mosquito Anopheles. The resistance of this species to synthetic insecticides contributes to an increase in the incidence of malaria and therefore necessitates the development of new potent and eco-friendly insecticides. In this study, twelve previously reported limonoids from four Entandrophragma species collected in Cameroon have been computationally evaluated for their Anopheles gambiae AChE inhibitory activity. The docking procedure was carried out through Molecular Operating Environment 2019.01 (MOE), while the UCSF Chimera program was used to model the docking results based on interactions between proteins and ligands, and molecular dynamics trajectories were analyzed using the GROMACS 2021.1 tool. Entandrophragmin and encandollens B and C with docking scores ranging from −6.45 to −7.28 kcal/mol were the most promising hits compared to the reference azadirachtin (−6.22 kcal/mol) and were further evaluated for their mechanism of action. Subsequent evaluation classified encandollen C as the best candidate for the development of new potent eco-friendly insecticides based on its lower average RMSD and RMSF and its compactness over a 150 ns duration with acetylcholinesterase. Full article

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AppliedChem, Volume 4, Issue 4 (December 2024) – 4 articles

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