| 1. |
- Bagnall, Andrew J., et al.
(author)
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Molecular Engineering of Electrocatalytic Nanomaterials for Hydrogen Evolution : The Impact of Structural and Electronic Modifications of Anchoring Linkers on Electrocatalysis
- 2024
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In: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 14:8, s. 5630-5638
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Journal article (peer-reviewed)abstract
- The anticipated shortage of an increasing number of critical elements, especially metals, requires a shift toward molecularly defined materials with low metal loadings. More particularly, surface-anchored molecular catalysts are attractive to prospectively enable cost-effective electrochemical hydrogen evolution. However, the design of ligands integrating specific anchoring unit(s) for the immobilization of molecular catalysts can be challenging and has direct consequences for the intrinsic properties of the grafted complex. In this work, two cobalt tetraazamacrocyclic complexes bearing pyrene anchoring groups at different positions on the macrocyclic ligands were synthesized. The pyrene unit allows for simple immobilization and electrochemical characterization of the two complexes on multi-walled carbon nanotube-based electrodes. Thorough electrochemical and electrocatalytic investigation demonstrates important differences between the two closely related catalysts in terms of catalyst loading, catalytic response, and stability over time, with a significantly higher stability observed at pH 7 than at pH 2.
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| 2. |
- Moghaddam, Navid Jameei, et al.
(author)
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A Chemical Evolution-Like Method to Synthesize a Water-Oxidizing Catalyst
- 2021
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In: ChemElectroChem. - : John Wiley & Sons. - 2196-0216. ; 8:23, s. 4612-4617
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Journal article (peer-reviewed)abstract
- The development of new procedures for synthesizing new, low-cost, and stable metal oxides for the oxygen-evolution reaction (OER) by water oxidation is critical. Since the 2000s, there has been a rapid rise in the use of first-row transition metal (hydr)oxides for the OER. However, there is still a need to design and synthesize an efficient and stable catalyst for the OER. The present paper aims to design and synthesize an OER catalyst based on "a look at nature" strategy. In a simple and chemical evolution-like experiment, for the first time, a solution composed of various perchlorate cations, namely, Li(I), Mg(II), Ca(II), Al(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ba(II), and Na2SiO3, at a concentration of 1.0 mM at pH=4 and a potential of 1.40 V vs. NHE, which was under stirring for 15 days, was investigated. The stable OER catalyst on the electrode was characterized by X-ray absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. Based on the extrapolation of the Tafel plot, the onset of the OER in the presence of this catalyst was 130 mV lower than a bare electrode without it. This approach could be a roadmap to design and synthesize new and stable catalysts.
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