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Quirós-Díez EP, Herreros-Lucas C, Vila-Fungueiriño JM, Vizcaíno-Anaya L, Sabater-Algarra Y, Giménez-López MDC. Boosting Oxygen Reduction Reaction Selectivity in Metal Nanoparticles with Polyoxometalates. Small Methods 2024:e2301805. [PMID: 38517266 DOI: 10.1002/smtd.202301805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/06/2024] [Indexed: 03/23/2024]
Abstract
The lack of selectivity toward the oxygen reduction reaction (ORR) in metal nanoparticles can be linked to the generation of intermediates. This constitutes a crucial constraint on the performance of specific electrochemical devices, such as fuel cells and metal-air batteries. To boost selectivity of metal nanoparticles, a novel methodology that harnesses the unique electrocatalytic properties of polyoxometalates (POM) to scavenge undesired intermediates of the ORR (such as HO2 -) promoting selectivity is proposed. It involves the covalent functionalization of metal nanoparticle's surface with an electrochemically active capping layer containing a new sulfur-functionalized vanadium-based POM (AuNP@POM). To demonstrate this approach, preformed thiolate Au(111) nanoparticles with a relatively poor ORR selectivity are chosen. The dispersion of AuNP@POM on the surface of carbon nanofibers (CNF) enhances oxygen diffusion, and therefore the ORR activity. The resulting electrocatalyst (AuNP@POM/CNF) exhibits superior stability against impurities like methanol and a higher pH tolerance range compared to the standard commercial Pt/C. The work demonstrates for the first time, the use of a POM-based electrochemically active capping layer to switch on the selectivity of poorly selective gold nanoparticles, offering a promising avenue for the preparation of electrocatalyst materials with improved selectivity, performance, and stability for ORR-based devices.
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Affiliation(s)
- Eugenia Pilar Quirós-Díez
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - Carlos Herreros-Lucas
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - José Manuel Vila-Fungueiriño
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Física, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - Lucía Vizcaíno-Anaya
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - Yolanda Sabater-Algarra
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - María Del Carmen Giménez-López
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
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Herreros-Lucas C, Vila-Fungueiriño JM, Giménez-López MDC. Electrochemically Versatile Graphite Nanoplatelets Prepared by a Straightforward, Highly Efficient, and Scalable Route. ACS Appl Mater Interfaces 2023; 15:21375-21383. [PMID: 37015345 PMCID: PMC10165606 DOI: 10.1021/acsami.2c22495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Nanostructured carbon materials with tailor-made structures (e.g., morphology, topological defect, dopant, and surface area) are of significant interest for a variety of applications. However, the preparation method selected for obtaining these tailor-made structures determines the area of application, precluding their use in other technological areas of interest. Currently, there is a lack of simple and low-cost methodologies versatile enough for obtaining freestanding carbon nanostructures that can be used in either energy storage or chemical detection. Here, a novel methodology for the development of a versatile electrochemically active platform based on freestanding graphite nanoplatelets (GNP) has been developed by exploiting the interiors of hollow carbon nanofibers (CNF) comprising nanographene stacks using dry ball-milling. Even though ball-milling could be considered as a universal method for any carbonaceous material, often, it is not as simple (one step, no purification, and no solvents), efficient (just GNP without tubular structures), and quick (just 20 min) as the sustainable method developed in this work, free of surfactants and stabilizer agents. We demonstrate that the freestanding GNP developed in this work (with an average thickness of 3.2 nm), due to the selective edge functionalization with the minimal disruption of the basal plane, can act either as a supercapacitor or as a chemical sensor, showing both a dramatic improvement in the charge storage ability of more than 30 times and an enhanced detection of electrochemically active molecules such as ascorbic acid with a 236 mV potential shift with respect to CNF in both cases. As shown here, GNP stand as an excellent versatile alternative compared to the standard commercially available carbon-based materials. Overall, our approach paves the way for the discovery of new nanocarbon-based electrochemical active platforms with a wide electrochemical applicability.
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Affiliation(s)
- Carlos Herreros-Lucas
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - José Manuel Vila-Fungueiriño
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - María Del Carmen Giménez-López
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, U.K
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Varela-Domínguez N, López-Bueno C, López-Moreno A, Claro MS, Rama G, Leborán V, Giménez-López MDC, Rivadulla F. Light-induced bi-directional switching of thermal conductivity in azobenzene-doped liquid crystal mesophases. J Mater Chem C Mater 2023; 11:4588-4594. [PMID: 37033203 PMCID: PMC10077501 DOI: 10.1039/d3tc00099k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/23/2023] [Indexed: 06/19/2023]
Abstract
The development of systems that can be switched between states with different thermal conductivities is one of the current challenges in materials science. Despite their enormous diversity and chemical richness, molecular materials have been only scarcely explored in this regard. Here, we report a reversible, light-triggered thermal conductivity switching of ≈30-40% in mesophases of pure 4,4'-dialkyloxy-3-methylazobenzene. By doping a liquid crystal matrix with the azobenzene molecules, reversible and bidirectional switching of the thermal conductivity can be achieved by UV/Vis-light irradiation. Given the enormous variety of photoactive molecules and chemically compatible liquid crystal mesophases, this approach opens unforeseen possibilities for developing effective thermal switches based on molecular materials.
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Affiliation(s)
- Noa Varela-Domínguez
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Fisica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - Carlos López-Bueno
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Fisica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - Alejandro López-Moreno
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Inorganica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - Marcel S Claro
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Fisica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - Gustavo Rama
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Inorganica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - Víctor Leborán
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - María Del Carmen Giménez-López
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Inorganica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
| | - Francisco Rivadulla
- CiQUS, Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Fisica, Universidade de Santiago de Compostela 15782-Santiago de Compostela Spain
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Zhang W, Guillén-Soler M, Moreno-Da Silva S, López-Moreno A, González LR, Giménez-López MDC, Pérez EM. Mechanical interlocking of SWNTs with N-rich macrocycles for efficient ORR electrocatalysis. Chem Sci 2022; 13:9706-9712. [PMID: 36091908 PMCID: PMC9400660 DOI: 10.1039/d2sc02346f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/23/2022] [Indexed: 12/05/2022] Open
Abstract
Substitutional N-doping of single-walled carbon nanotubes is a common strategy to enhance their electrocatalytic properties in the oxygen-reduction reaction (ORR). Here, we explore the encapsulation of SWNTs within N-rich macrocycles as an alternative strategy to display electroactive sites on the surface of SWNTs. We design and synthesize four types of mechanically interlocked derivatives of SWNTs (MINTs) by combining two types of macrocycles and two types of SWNT samples. Comprehensive electrochemical characterization of these MINTs and their reference SWNTs allows us to establish structure-activity relationships. First, we show that all MINT samples are superior electrocatalysts compared to pristine SWNTs, which serves as general validation of our strategy. Secondly, we show that macrocycles displaying both N atoms and carbonyl groups perform better than those with N atoms only. Finally, we demonstrate that a tighter fit between macrocycles and SWNTs results in enhanced catalytic activity and stability, most likely due to a more effective charge-transfer between the SWNTs and the macrocycles. These results, focusing on the ORR as a testbed, show the possibility of understanding electrocatalytic performance of SWNTs at the molecular level and thus enable the design of more active and more stable catalysts in the future.
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Affiliation(s)
| | - Melanie Guillén-Soler
- CIQUS, Universidad de Santiago de Compostela Rua Jenaro de la Fuente Santiago de Compostela 15782 Spain
| | | | | | - Luisa R González
- Departamento de Química Inorgánica, Universidad Complutense de Madrid Madrid 28040 Spain
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López-Bueno C, Bittermann MR, Dacuña-Mariño B, Llamas-Saiz AL, Del Carmen Giménez-López M, Woutersen S, Rivadulla F. Low temperature glass/crystal transition in ionic liquids determined by H-bond vs. coulombic strength. Phys Chem Chem Phys 2020; 22:20524-20530. [PMID: 32966417 DOI: 10.1039/d0cp02633f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembled ionic liquid crystals are anisotropic ionic conductors, with potential applications in areas as important as solar cells, battery electrolytes and catalysis. However, many of these applications are still limited by the lack of precise control over the variety of phases that can be formed (nematic, smectic, or semi/fully crystalline), determined by a complex pattern of different intermolecular interactions. Here we report the results of a systematic study of crystallization of several imidazolium salts in which the relative contribution of isotropic coulombic and directional H-bond interactions is carefully tuned. Our results demonstrate that the relative strength of directional H-bonds with respect to the isotropic Coulomb interaction determines the formation of a crystalline, semi-crystalline or glassy phase at low temperature. The possibility of pinpointing H-bonding directionality in ionic liquids make them model systems to study the crystallization of an ionic solid under a perturbed Coulomb potential.
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Affiliation(s)
- Carlos López-Bueno
- CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
| | - Marius R Bittermann
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bruno Dacuña-Mariño
- X-Ray Unit, RIAIDT, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | | | - María Del Carmen Giménez-López
- CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain. and Departamento de Química-Inorgánica, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain
| | - Sander Woutersen
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Francisco Rivadulla
- CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain. and Departamento de Química-Física, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain
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