Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media

Hernández-García, Fabiola; Sanchez-Mora, Arturo T.; Serrano-García, Juan S.; Amaya-Florez, Andrés; Ortiz-Frade, Luis A.; Alvarez-Romero, Giaan A.; Cruz-Navarro, J. Antonio; Morales-Morales, David

doi:10.3390/pr12071466

Open AccessArticle

Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media

by

Fabiola Hernández-García

¹,

Arturo T. Sanchez-Mora

²

,

Juan S. Serrano-García

²

,

Andrés Amaya-Florez

²

,

Luis A. Ortiz-Frade

³,

Giaan A. Alvarez-Romero

^1,*

,

J. Antonio Cruz-Navarro

^2,*

and

David Morales-Morales

^2,*

¹

Área Académica de Química, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico

²

Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior s/n, Ciudad de Mexico 04510, Mexico

³

Centro de Investigaciones y Desarrollo Tecnológico en Electroquímica CIDETEQ, Parque Tecnológico Querétaro s/n Sanfandila, Pedro Escobedo 76703, Querétaro, Mexico

^*

Authors to whom correspondence should be addressed.

Processes 2024, 12(7), 1466; https://doi.org/10.3390/pr12071466

Submission received: 17 April 2024 / Revised: 8 July 2024 / Accepted: 10 July 2024 / Published: 13 July 2024

(This article belongs to the Special Issue New Research on Transition Metal Catalysis and Green Synthesis)

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Abstract

The application of organometallic materials as anodes in fuel cell devices has experienced a notable increase in recent years. However, the use of POCOP pincer complexes remains scarcely explored despite their great relevance in catalysis. Thus, in this work, the electrocatalytic activity to methanol in alkaline media of three Ni(II)-based POCOP pincer complexes—[NiCl{C₆H₂-4-OH-2,6-(OPiPr₂)₂}] (a1), [NiCl{C₆H₂-4-OH-2,6-(OPtBu₂)₂}] (a2), and [NiCl{C₆H₂-4-OH-2,6-(OPPh₂)₂}] (a3)—will be discussed. The complexes were use as modifiers of carbon paste electrodes that were evaluated using cyclic voltammetry considering diverse factors, such as the absence and presence of MeOH, diverse proportions (% w/w) of the complex in the electrode, scan rate, and different MeOH concentrations. Results indicated the presence of a redox pair Ni(II)/Ni(III) with a quasi-reversible behavior in all complexes, the anodic peak currents of which were proportional to the increase in MeOH concentrations (0.05–0.3 mM), and their oxidation potentials varied in the function of the P-substituent in the Ni(II)-POCOPs backbone. Complex a1 exhibited the best current density (429.5 mA cm² at 0.5 mM) compared to its analogs a2 and a3. The current intensity of all electrodes displays good stability, which remains—with slight changes—up to 100 s. Moreover, a comparison of their catalytic rate constants suggested a great activity in complex a1 (0.52 × 10⁶ cm³ mol⁻¹ s⁻¹) compared to its analogues, implying a great activity in the electro-oxidation of MeOH. Hence, this work opens new opportunities for the electrochemical application of POCOPs complexes for future DMFCs development.

Keywords: modified electrodes; methanol electro-oxidation; pincer complexes; electrocatalysis

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MDPI and ACS Style

Hernández-García, F.; Sanchez-Mora, A.T.; Serrano-García, J.S.; Amaya-Florez, A.; Ortiz-Frade, L.A.; Alvarez-Romero, G.A.; Cruz-Navarro, J.A.; Morales-Morales, D. Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media. Processes 2024, 12, 1466. https://doi.org/10.3390/pr12071466

AMA Style

Hernández-García F, Sanchez-Mora AT, Serrano-García JS, Amaya-Florez A, Ortiz-Frade LA, Alvarez-Romero GA, Cruz-Navarro JA, Morales-Morales D. Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media. Processes. 2024; 12(7):1466. https://doi.org/10.3390/pr12071466

Chicago/Turabian Style

Hernández-García, Fabiola, Arturo T. Sanchez-Mora, Juan S. Serrano-García, Andrés Amaya-Florez, Luis A. Ortiz-Frade, Giaan A. Alvarez-Romero, J. Antonio Cruz-Navarro, and David Morales-Morales. 2024. "Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media" Processes 12, no. 7: 1466. https://doi.org/10.3390/pr12071466

APA Style

Hernández-García, F., Sanchez-Mora, A. T., Serrano-García, J. S., Amaya-Florez, A., Ortiz-Frade, L. A., Alvarez-Romero, G. A., Cruz-Navarro, J. A., & Morales-Morales, D. (2024). Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media. Processes, 12(7), 1466. https://doi.org/10.3390/pr12071466

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Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media

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