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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Calvillo, Laura
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (15/15 displayed)
- 2022Harnessing Molecular Fluorophores in the Carbon Dots Matrix: The Case of Safranin Ocitations
- 2021Electrocatalytic Site Activity Enhancement via Orbital Overlap in A 2 MnRuO 7 (A = Dy 3+ , Ho 3+ , and Er 3+ ) Pyrochlore Nanostructurescitations
- 2021Electrocatalytic Site Activity Enhancement via Orbital Overlap in A 2MnRuO 7(A = Dy 3+, Ho 3+, and Er 3+) Pyrochlore Nanostructurescitations
- 2018Graphene Oxide/Iron Oxide Nanocomposites for Water Remediationcitations
- 2018Aerosol Synthesis of N and N-S Doped and Crumpled Graphene Nanostructurescitations
- 2017YFeO3 Photocathodes for Hydrogen Evolutioncitations
- 2017Ag-Vanadates/GO Nanocomposites by Aerosol-Assisted Spray Pyrolysis: Preparation and Structural and Electrochemical Characterization of a Versatile Materialcitations
- 2017YFeO 3 Photocathodes for Hydrogen Evolutioncitations
- 2016VO <sub>2</sub> /V <sub>2</sub> O <sub>5</sub> :Ag Nanostructures on a DVD as Photoelectrochemical Sensorscitations
- 2016Influence of thermal treatments on the stability of Pd nanoparticles supported on graphitised ordered mesoporous carbonscitations
- 2016Influence of thermal treatments on the stability of Pd nanoparticles supported on graphitised ordered mesoporous carbonscitations
- 2016Fabrication of Ti substrate grain dependent C/TiO2 composites through carbothermal treatment of anodic TiO2citations
- 2016Cu2O/TiO2 heterostructures on a DVD as easy&cheap photoelectrochemical sensorscitations
- 2016A Highly Efficient and Stable Oxygen Reduction Reaction on Pt/CeOx/C Electrocatalyst Obtained via a Sacrificial Precursor Based on a Metal-Organic Frameworkcitations
- 2015Fast One-Pot Synthesis of MoS2/Crumpled Graphene p-n Nanonjunctions for Enhanced Photoelectrochemical Hydrogen Productioncitations
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article
Electrocatalytic Site Activity Enhancement via Orbital Overlap in A 2MnRuO 7(A = Dy 3+, Ho 3+, and Er 3+) Pyrochlore Nanostructures
Abstract
Oxygen electrocatalysis at transition metal oxides is one of the key challenges underpinning electrochemical energy conversion systems, involving a delicate interplay of bulk electronic structure and surface coordination of the active sites. In this work, we investigate for the first time the structure-activity relationship of A2RuMnO7 (A = Dy3+, Ho3+, Er3+) nanoparticles, demonstrating how orbital mixing of Ru, Mn, and O promotes high density of states (DOS) at the appropriate energy range for oxygen electrocatalysis. The bulk and surface structure of these multicomponent pyrochlores are investigated by high-resolution transmission electron microscopy, X-ray diffraction, X-ray absorption (XAS), X-ray emission (XES) and X-ray photoemission (XPS) spectroscopies. The materials exhibit high phase purity (cubic fcc with a space group Fd3 ̅m), in which variations in M-O bonds length are less than 1% upon replacing the A-site lanthanide. XES and XPS show that the mean oxidation state at the Mn-site as well as the nanoparticle surface composition were slightly affected by the lanthanide. The pyrochlore nanoparticles are significantly more active than the binary RuO2 and MnO2 towards the 4-electron oxygen reduction reaction (ORR) in alkaline solutions. Interestingly, normalization of kinetic parameters by the number density of electroactive sites concludes that Dy2RuMnO7 shows twice higher activity than benchmark materials such as LaMnO3. Analysis of the electrochemical profiles supported by DFT calculations reveals that the origin of the enhanced catalytic activity is linked to the mixing of Ru and Mn d-orbitals and O p-orbitals at the conduction band which strongly overlap with the formal redox energy of O2 in solution. The activity enhancement strongly manifests in the case of Dy2RuMnO7 where Ru/Mn ratio is closer to 1 in comparison with the Ho3+ and Er3+ analogs. These electronic effects are discussed in the context of the Gerischer formalism for electron transfer at the semiconductor/electrolyte junctions.