Quantum Chemical Characterization of Water Oxidation Catalysts

Miró, Pere; Ertem, Mehmed Z.; Gagliardi, Laura; Cramer, Christopher J.

doi:10.1002/9781118698648.ch12

Cited by 3 publications

(3 citation statements)

References 79 publications

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“…We note that an error of ca. 300 mV is within the accuracy reported in previous theoretical works 55 . This choice of functional, in concert with the chosen basis sets is further supported by the satisfactory results obtained in the computation of heats of formation of many different transition metal complexes 75 .…”

Section: Methodssupporting

confidence: 90%

“…In the following, however, we demonstrate that this unsuspected behavior is caused by an oversimplification of the reaction mechanism, typically assumed in most theoretical studies of heterogeneous OER catalysts. Notably, some metals, such as Ru, Mn, or Fe, have been experimentally proven to undergo an additional one-electron transfer (ET) before O-O bond formation [52][53][54][55] . Bearing this in mind, we computed (whenever possible) the Gibbs energies for the ET from the M(IV)-oxo to M(V)-oxo species with M = Ru, Mn, Fe, hereafter referred to as O(IV) Ã and O(V) Ã , respectively (see Supplementary Tables 2 and 3 for details).…”

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confidence: 99%

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Universal scaling relations for the rational design of molecular water oxidation catalysts with near-zero overpotential

et al. 2019

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A major roadblock in realizing large-scale production of hydrogen via electrochemical water splitting is the cost and inefficiency of current catalysts for the oxygen evolution reaction (OER). Computational research has driven important developments in understanding and designing heterogeneous OER catalysts using linear scaling relationships derived from computed binding energies. Herein, we interrogate 17 of the most active molecular OER catalysts, based on different transition metals (Ru, Mn, Fe, Co, Ni, and Cu), and show they obey similar scaling relations to those established for heterogeneous systems. However, we find that the conventional OER descriptor underestimates the activity for very active OER complexes as the standard approach neglects a crucial one-electron oxidation that many molecular catalysts undergo prior to O-O bond formation. Importantly, this additional step allows certain molecular catalysts to circumvent the "overpotential wall", leading to enhanced performance. With this knowledge, we establish fundamental principles for the design of ideal molecular OER catalysts.

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Section: Methodssupporting

confidence: 90%

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confidence: 99%

Universal scaling relations for the rational design of molecular water oxidation catalysts with near-zero overpotential

et al. 2019

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“…DFT studies on the complete catalytic cycle for homogeneous OER catalysts have also been reported, although they are scarce. Cramer and co-workers [30]…”

Section: Introductionmentioning

confidence: 99%

Computational modelling of water oxidation catalysts

Soriano-López

Schmitt

García‐Melchor

2018

Current Opinion in Electrochemistry

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In this opinion, we review the state-of-the-art in the modelling of the water oxidation reaction catalysed by homogeneous and heterogeneous systems. We start by introducing the potential and current limitations in the development of energy conversion technologies based on this process, followed by a brief description of the two main proposed reaction mechanisms. We next present an overview of the different theoretical approaches adopted to describe this reaction, and summarise the most recent computational works devoted specifically to the investigation of the O-O bond formation step. This latter part also includes a review of the advances in the modelling of electrochemical energy barriers. The chemical descriptors proposed to rationalise the OER activity and the theoretical methods developed to account for solvent effects, are also reviewed. Finally, we present a selection of theoretical studies reported over the last two years to illustrate the descriptive and predictive power of computational methods.

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Electrocatalytic Isoxazoline–Nanocarbon Metal Complexes

et al. 2021

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We report the synthesis of new carbon-nanomaterial-based metal chelates that enable effective electronic coupling to electrocatalytic transition metals. In particular, multiwalled carbon nanotubes (MWCNTs) and few-layered graphene (FLG) were covalently functionalized by a microwave-assisted cycloaddition with nitrile oxides to form metal-binding isoxazoline functional groups with high densities. The covalent attachment was evidenced by Raman spectroscopy, and the chemical identity of the surface functional groups was confirmed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The functional carbon nanomaterials effectively chelate precious metals Ir(III), Pt(II), and Ru(III), as well as earth-abundant metals such as Ni(II), to afford materials with metal contents as high as 3.0 atom %. The molecularly dispersed nature of the catalysts was confirmed by X-ray absorption spectroscopy (XAS) and energy-dispersive X-ray spectroscopy (STEM-EDS) elemental mapping. The interplay between the chelate structure on the graphene surface and its metal binding ability has also been investigated by a combination of experimental and computational studies. The defined ligands on the graphene surfaces enable the formation of structurally precise heterogeneous molecular catalysts. The direct attachment of the isoxazoline functional group on the graphene surfaces provides strong electronic coupling between the chelated metal species and the conductive carbon nanomaterial support. We demonstrate that the metal-chelated carbon nanomaterials are effective heterogeneous catalysts in the oxygen evolution reaction with low overpotentials and tunable catalytic activity.

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Quantum Chemical Characterization of Water Oxidation Catalysts

Cited by 3 publications

References 79 publications

Universal scaling relations for the rational design of molecular water oxidation catalysts with near-zero overpotential

Universal scaling relations for the rational design of molecular water oxidation catalysts with near-zero overpotential

Computational modelling of water oxidation catalysts

Electrocatalytic Isoxazoline–Nanocarbon Metal Complexes

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