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Nanomaterials for Electrocatalytic Applications

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Nanochemistry".

Deadline for manuscript submissions: 30 June 2024 | Viewed by 11962

Special Issue Editor


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Guest Editor
Systems and Process Engineering Centre, College of Engineering, Swansea University, Bay Campus, Crymlyn Burrows, Swansea SA1 8EN, UK
Interests: electrochemiluminescence; sensors; thin films; electrochemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Electrocatalysis is the branch of science that investigates the chemical reactions occurring at the surface of various nanomaterials from metal and metal oxide nanoparticles, to other nanomaterials with applications ranging from reactions of interest in energy (hydrogen oxidation, oxygen reduction reactions) but also in analytical chemistry, for example, sensors for the detection of analytes of clinical relevance. This Special Issue aims at collecting reviews and recent works on the most recent development in electrocatalysis studies applied to energy and sensing applications.

Dr. Paolo Bertoncello
Guest Editor

Manuscript Submission Information

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Keywords

  • Electrocatalysis
  • Amperometric sensors
  • Oxygen reduction reactions
  • Hydrogen evolution and hydrogen oxidation reactions
  • Chemically modified electrodes
  • Nanomaterials

Published Papers (6 papers)

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Research

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12 pages, 5254 KiB  
Article
Self–Supporting Mn–RuO2 Nanoarrays for Stable Oxygen Evolution Reaction in Acid
by Mengting Deng, Yulong Tang, Zhiyi Lu, Yunan Wang and Yichao Lin
Molecules 2023, 28(23), 7727; https://doi.org/10.3390/molecules28237727 - 23 Nov 2023
Cited by 1 | Viewed by 934
Abstract
Currently, the process of an acidic oxygen evolution reaction (OER) necessitates the use of Iridium dioxygen (IrO2), which is both expensive and incredibly scarce on Earth. Ruthenium dioxygen (RuO2) offers high activity for acidic OERs and presents a potential [...] Read more.
Currently, the process of an acidic oxygen evolution reaction (OER) necessitates the use of Iridium dioxygen (IrO2), which is both expensive and incredibly scarce on Earth. Ruthenium dioxygen (RuO2) offers high activity for acidic OERs and presents a potential substitution for IrO2. Nevertheless, its practical application is hindered by its relatively poor stability. In this study, we have developed Mn–doped RuO2 (Mn–RuO2) nanoarrays that are anchored on a titanium (Ti) mesh utilizing a two–step methodology involving the preparation of MnO2 nanoarrays followed by a subsequent Ru exchange and annealing process. By precisely optimizing the annealing temperature, we have managed to attain a remarkably low overpotential of 217 mV at 10 mA cm−2 in a 0.5 M H2SO4 solution. The enhanced catalytic activity of our Mn–RuO2 nanoarrays can be attributed to the electronic modification brought about by the high exposure of active sites, Mn dopant, efficient mass transfer, as well as the efficient transfer of electrons between the Ti mesh and the catalyst arrays. Furthermore, these self–supported Mn–RuO2 nanoarrays demonstrated excellent long–term stability throughout a chronoamperometry test lasting for 100 h, with no discernible changes observed in the Ru chemical states. Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications)
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12 pages, 2298 KiB  
Article
Asymmetric Push–Pull Type Co(II) Porphyrin for Enhanced Electrocatalytic CO2 Reduction Activity
by Chenjiao Huang, Wenwen Bao, Senhe Huang, Bin Wang, Chenchen Wang, Sheng Han, Chenbao Lu and Feng Qiu
Molecules 2023, 28(1), 150; https://doi.org/10.3390/molecules28010150 - 24 Dec 2022
Cited by 1 | Viewed by 2022
Abstract
Molecular electrocatalysts for electrochemical carbon dioxide (CO2) reduction has received more attention both by scientists and engineers, owing to their well-defined structure and tunable electronic property. Metal complexes via coordination with many π-conjugated ligands exhibit the unique electrocatalytic CO2 reduction [...] Read more.
Molecular electrocatalysts for electrochemical carbon dioxide (CO2) reduction has received more attention both by scientists and engineers, owing to their well-defined structure and tunable electronic property. Metal complexes via coordination with many π-conjugated ligands exhibit the unique electrocatalytic CO2 reduction performance. The symmetric electronic structure of this metal complex may play an important role in the CO2 reduction. In this work, two novel dimethoxy substituted asymmetric and cross-symmetric Co(II) porphyrin (PorCo) have been prepared as the model electrocatalyst for CO2 reduction. Owing to the electron donor effect of methoxy group, the intramolecular charge transfer of these push–pull type molecules facilitates the electron mobility. As electrocatalysts at −0.7 V vs. reversible hydrogen electrode (RHE), asymmetric methoxy-substituted Co(II) porphyrin shows the higher CO2-to-CO Faradaic efficiency (FECO) of ~95 % and turnover frequency (TOF) of 2880 h−1 than those of control materials, due to its push–pull type electronic structure. The density functional theory (DFT) calculation further confirms that methoxy group could ready to decrease to energy level for formation *COOH, leading to high CO2 reduction performance. This work opens a novel path to the design of molecular catalysts for boosting electrocatalytic CO2 reduction. Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications)
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14 pages, 2522 KiB  
Article
Facile Controlled Synthesis of Pd-ZnO Nanostructures for Nitrite Detection
by Yaojuan Hu, Fengyun He, Changyun Chen, Changli Zhang and Jingliang Liu
Molecules 2023, 28(1), 99; https://doi.org/10.3390/molecules28010099 - 23 Dec 2022
Cited by 2 | Viewed by 1547
Abstract
The electrocatalytic characteristics of nanostructures are significantly affected by surface structure. The strict regulation of structural characteristics is highly beneficial for the creation of novel nanocatalysts with enhanced electrocatalytic performance. This work reports a nitrite electrochemical sensor based on novel flower-like Pd-ZnO nanostructures. [...] Read more.
The electrocatalytic characteristics of nanostructures are significantly affected by surface structure. The strict regulation of structural characteristics is highly beneficial for the creation of novel nanocatalysts with enhanced electrocatalytic performance. This work reports a nitrite electrochemical sensor based on novel flower-like Pd-ZnO nanostructures. The Pd-ZnO nanocatalysts were synthesized through a simple hydrothermal method, and their morphology and structure were characterized via field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Their electrocatalytical performance in the nitrite oxidation reaction was studied via cyclic voltammetry (CV) and the amperometric technique. Compared to pure ZnO and Pd nanoparticles, the Pd-ZnO nanostructures exhibited enhanced electrochemical performance in the nitrite oxidation reaction. In order to investigate the relationships between the structures of Pd-ZnO nanocatalysts and the corresponding electrocatalytic performances, different surface morphologies of Pd-ZnO nanocatalysts were fabricated by altering the solution pH. It was found that the flower-like Pd-ZnO nanostructures possessed larger effective surface areas and faster electron transfer rates, resulting in the highest electrocatalytic performance in the nitrite oxidation reaction. The designed nitrite sensor based on flower-like Pd-ZnO displayed a wide concentration linear range of 1 μM–2350 μM, a low detection limit of 0.2 μM (S/N of 3), and high sensitivity of 151.9 μA mM−1 cm−2. Furthermore, the proposed sensor exhibited perfect selectivity, excellent reproducibility, and long-time stability, as well as good performance in real sample detection. Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications)
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10 pages, 6221 KiB  
Article
Morphology-Controlled Synthesis of V1.11S2 for Electrocatalytic Hydrogen Evolution Reaction in Acid Media
by Qiuyue Chen, Siqi Tian, Xiaonan Liu, Xuguang An, Jingxian Zhang, Longhan Xu, Weitang Yao and Qingquan Kong
Molecules 2022, 27(22), 8019; https://doi.org/10.3390/molecules27228019 - 18 Nov 2022
Cited by 1 | Viewed by 1142
Abstract
High-performance low-cost catalysts are in high demand for the hydrogen evolution reaction (HER). In the present study, we reported that V1.11S2 materials with flower-like, flake-like, and porous morphologies were successfully synthesized by hydrothermal synthesis and subsequent calcination. The effects of [...] Read more.
High-performance low-cost catalysts are in high demand for the hydrogen evolution reaction (HER). In the present study, we reported that V1.11S2 materials with flower-like, flake-like, and porous morphologies were successfully synthesized by hydrothermal synthesis and subsequent calcination. The effects of morphology on hydrogen evolution performance were studied. Results show that flower-like V1.11S2 exhibits the best electrocatalytic activity for HER, achieving both high activity and preferable stability in 0.5 M H2SO4 solution. The main reason can be ascribed to the abundance of catalytically active sites and low charge transfer resistance. Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications)
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15 pages, 4435 KiB  
Article
Transition Metal Substituted Barium Hexaferrite-Modified Electrode: Application as Electrochemical Sensor of Acetaminophen
by Claudia Patricia Granja-Banguera, Daniel Gerardo Silgado-Cortázar and Jimmy Alexander Morales-Morales
Molecules 2022, 27(5), 1550; https://doi.org/10.3390/molecules27051550 - 25 Feb 2022
Cited by 11 | Viewed by 2441
Abstract
This study used substituted barium hexaferrites, which were previously prepared and reported by the authors, to detect acetaminophen by the modification of a conventional glassy carbon electrode (GCE), which led to promising results. The synthesis of this electrode-modifying material was conducted using a [...] Read more.
This study used substituted barium hexaferrites, which were previously prepared and reported by the authors, to detect acetaminophen by the modification of a conventional glassy carbon electrode (GCE), which led to promising results. The synthesis of this electrode-modifying material was conducted using a citrate sol gel process. A test synthesis using glycerin and propylene glycol revealed that glycerin produced a better result, while less positive anodic potential values were associated with the electrooxidation of N-acetyl-p-aminophenol (NAP). Excellent electroactivity was exhibited by the cobalt-substituted barium-hexaferrite-nanomaterial-modified electrode. A good linear relationship between the concentration and the current response of acetaminophen (paracetamol) was obtained with a detection limit of (0.255 ± 0.005) µM for the Ba1.0Co1.22Fe11.41O18.11 GCE, (0.577 ± 0.007) µM for the Ba1.14Cu0.82Fe11.65O18.02 GCE, and (0.595 ± 0.008) µM for the bare GCE. The levels of NAP in a real sample of urine were quantitatively analyzed using the proposed method, with recovery ranges from 96.6% to 101.0% and 93.9% to 98.4% for the modified electrode with Cobalt-substituted barium hexaferrites (CoFM) and Copper-substituted barium hexaferrites (CuFM), respectively. These results confirm the high electrochemical activity of Ba1.0Co1.22Fe11.41O18.11 nanoparticles and thus their potential for use in the development of sensing devices for substances of pharmaceutical interest, such as acetaminophen (NAP). Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications)
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Review

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17 pages, 4408 KiB  
Review
Enhanced Electrocatalytic Detection of Choline Based on CNTs and Metal Oxide Nanomaterials
by Gloria E. Uwaya and Omolola E. Fayemi
Molecules 2021, 26(21), 6512; https://doi.org/10.3390/molecules26216512 - 28 Oct 2021
Cited by 1 | Viewed by 2472
Abstract
Choline is an officially established essential nutrient and precursor of the neurotransmitter acetylcholine. It is employed as a cholinergic activity marker in the early diagnosis of brain disorders such as Alzheimer’s and Parkinson’s disease. Low levels of choline in diets and biological fluids, [...] Read more.
Choline is an officially established essential nutrient and precursor of the neurotransmitter acetylcholine. It is employed as a cholinergic activity marker in the early diagnosis of brain disorders such as Alzheimer’s and Parkinson’s disease. Low levels of choline in diets and biological fluids, such as blood plasma, urine, cerebrospinal and amniotic fluid, could be an indication of neurological disorder, fatty liver disease, neural tube defects and hemorrhagic kidney necrosis. Meanwhile, it is known that choline metabolism involves oxidation, which frees its methyl groups for entrance into single-C metabolism occurring in three phases: choline oxidase, betaine synthesis and transfer of methyl groups to homocysteine. Electrocatalytic detection of choline is of physiological and pathological significance because choline is involved in the physiological processes in the mammalian central and peripheral nervous systems and thus requires a more reliable assay for its determination in biological, food and pharmaceutical samples. Despite the use of several methods for choline determination, the superior sensitivity, high selectivity and fast analysis response time of bioanalytical-based sensors invariably have a comparative advantage over conventional analytical techniques. This review focuses on the electrocatalytic activity of nanomaterials, specifically carbon nanotubes (CNTs), CNT nanocomposites and metal/metal oxide-modified electrodes, towards choline detection using electrochemical sensors (enzyme and non-enzyme based), and various electrochemical techniques. From the survey, the electrochemical performance of the choline sensors investigated, in terms of sensitivity, selectivity and stability, is ascribed to the presence of these nanomaterials. Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications)
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