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Reuillard B, Costentin C, Artero V. Deciphering Reversible Homogeneous Catalysis of the Electrochemical H 2 Evolution and Oxidation: Role of Proton Relays and Local Concentration Effects. Angew Chem Int Ed Engl 2023; 62:e202302779. [PMID: 37073946 DOI: 10.1002/anie.202302779] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 04/20/2023]
Abstract
Nickel bisdiphosphine complexes bearing pendant amines form a unique series of catalysts (so-called DuBois' catalysts) capable of bidirectional/reversible electrocatalytic oxidation and production of dihydrogen. This unique behaviour is directly linked to the presence of proton relays installed close to the metal center. We report here for the arginine derivative [Ni(P2 Cy N2 Arg )2 ]6+ on a mechanistic model and its kinetic treatment that may apply to all DuBois' catalysts and show that it allows for a good fit of experimental data measured at different pH values, catalyst concentrations and partial hydrogen pressures. The bidirectionality of catalysis results from balanced equilibria related to hydrogen uptake/evolution on one side and (metal)-hydride installation/capture on the other side, both controlled by concentration effects resulting from the presence of proton relays and connected by two square schemes corresponding to proton-coupled electron transfer processes. We show that the catalytic bias is controlled by the kinetic of the H2 uptake/evolution step. Reversibility does not require that the energy landscape be flat, with redox transitions occurring at potentials up to 250 mV away for the equilibrium potential, although such large deviations from a flat energy landscape can negatively impacts the rate of catalysis when coupled with slow interfacial electron transfer kinetics.
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Affiliation(s)
| | | | - Vincent Artero
- Univ Grenoble Alpes, CNRS, CEA, IRIG, LCBM, 38000, Grenoble, France
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Zamader A, Reuillard B, Pécaut J, Billon L, Bousquet A, Berggren G, Artero V. Non-Covalent Integration of a [FeFe]-Hydrogenase Mimic to Multiwalled Carbon Nanotubes for Electrocatalytic Hydrogen Evolution. Chemistry 2022; 28:e202202260. [PMID: 36069308 PMCID: PMC10092503 DOI: 10.1002/chem.202202260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Indexed: 12/14/2022]
Abstract
Surface integration of molecular catalysts inspired from the active sites of hydrogenase enzymes represents a promising route towards developing noble metal-free and sustainable technologies for H2 production. Efficient and stable catalyst anchoring is a key aspect to enable this approach. Herein, we report the preparation and electrochemical characterization of an original diironhexacarbonyl complex including two pyrene groups per catalytic unit in order to allow for its smooth integration, through π-interactions, onto multiwalled carbon nanotube-based electrodes. In this configuration, the grafted catalyst could reach turnover numbers for H2 production (TONH2 ) of up to 4±2×103 within 20 h of bulk electrolysis, operating at neutral pH. Post operando analysis of catalyst functionalized electrodes revealed the degradation of the catalytic unit occurred via loss of the iron carbonyl units, while the anchoring groups and most part of the ligand remained attached onto multiwalled carbon nanotubes.
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Affiliation(s)
- Afridi Zamader
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, F-38054, Grenoble, Cedex, France.,Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden
| | - Bertrand Reuillard
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, F-38054, Grenoble, Cedex, France
| | - Jacques Pécaut
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-SyMMES, UMR 5819, 38000, Grenoble, France
| | - Laurent Billon
- Universite Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, 64000, Pau, France.,Bio-inspired Materials Group: Functionalities & Self-Assembly, Universite de Pau et Pays de l'Adour, E2S UPPA, 64053, Pau, France
| | - Antoine Bousquet
- Bio-inspired Materials Group: Functionalities & Self-Assembly, Universite de Pau et Pays de l'Adour, E2S UPPA, 64053, Pau, France
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden
| | - Vincent Artero
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, F-38054, Grenoble, Cedex, France
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Wiedner ES, Appel AM, Raugei S, Shaw WJ, Bullock RM. Molecular Catalysts with Diphosphine Ligands Containing Pendant Amines. Chem Rev 2022; 122:12427-12474. [PMID: 35640056 DOI: 10.1021/acs.chemrev.1c01001] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Pendant amines play an invaluable role in chemical reactivity, especially for molecular catalysts based on earth-abundant metals. As inspired by [FeFe]-hydrogenases, which contain a pendant amine positioned for cooperative bifunctionality, synthetic catalysts have been developed to emulate this multifunctionality through incorporation of a pendant amine in the second coordination sphere. Cyclic diphosphine ligands containing two amines serve as the basis for a class of catalysts that have been extensively studied and used to demonstrate the impact of a pendant base. These 1,5-diaza-3,7-diphosphacyclooctanes, now often referred to as "P2N2" ligands, have profound effects on the reactivity of many catalysts. The resulting [Ni(PR2NR'2)2]2+ complexes are electrocatalysts for both the oxidation and production of H2. Achieving the optimal benefit of the pendant amine requires that it has suitable basicity and is properly positioned relative to the metal center. In addition to the catalytic efficacy demonstrated with [Ni(PR2NR'2)2]2+ complexes for the oxidation and production of H2, catalysts with diphosphine ligands containing pendant amines have also been demonstrated for several metals for many different reactions, both in solution and immobilized on surfaces. The impact of pendant amines in catalyst design continues to expand.
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