Efficient H2-producing photocatalytic systems based on cyclometalated iridium- and tricarbonylrhenium-diimine photosensitizers and cobaloxime catalysts

Fihri, Aziz; Artero, Vincent; Pereira, Alexandre; Fontecave, Marc

doi:10.1039/b812605b

Cited by 233 publications

(225 citation statements)

References 17 publications

Supporting

Mentioning

210

Contrasting

Unclassified

Order By: Relevance

“…catalytic efficiency can be tuned. [20][21][22][23][24][25] The intensively studied intramolecular photocatalyst [(tbbpy) 2 Ru(tpphz)PdCl 2 ](PF 6 ) 2 (Fig. 1, Ru(tpphz)PdCl 2 ; tbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine, tpphz = tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2′′′,3′′′-j]phenazine) is an active hydrogen evolving PDM generating H 2 with a maximum turnover number (TON) of 238.…”

Section: Introductionmentioning

confidence: 99%

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

et al. 2014

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

et al. 2014

View full text Add to dashboard Cite

“…Different ligands have been proposed for Ru, the most common ones being polypyridyl or mixed pyridyl-CO complexes. Other metals have been also proposed, such as Re, Pt, and Ir, showing very high photoactivity for H 2 evolution [101][102][103]. Unfortunately most of these systems did not prove stable under irradiation [104] and leaching of the dye was often observed.…”

Section: Materials and Mechanismsmentioning

confidence: 99%

Hydrogen Production by Photoreforming of Renewable Substrates

Rossetti

2012

ISRN Chemical Engineering

View full text Add to dashboard Cite

This paper focuses on the application of photocatalysis to hydrogen production from organic substrates. This process, usually called photoreforming, makes use of semiconductors to promote redox reactions, namely, the oxidation of organic molecules and the reduction of H + to H 2 . This may be an interesting and fully sustainable way to produce this interesting fuel, provided that materials efficiency becomes sufficient and solar light can be effectively harvested. After a first introduction to the key features of the photoreforming process, the attention will be directed to the needs for materials development correlated to the existing knowledge on reaction mechanisms. Examples are then given on the photoreforming of alcohols, the most studied topic, especially in the case of methanol and carbohydrates. Finally, some examples of more complex but more interesting substrates, such as waste solutions, are proposed.

show abstract

“…[3][4][5][6][7][8] Cobaloximes are perspective and popular hydrogen evolving molecular catalysts [7][8][9] and they have been implemented in many homogeneous multicomponent photocatalytic systems. [7,[10][11][12][13][14][15][16] (Fig. 1, top panel).…”

mentioning

confidence: 99%

Microsecond X‐ray Absorption Spectroscopy Identification of Co^I Intermediates in Cobaloxime‐Catalyzed Hydrogen Evolution

Smolentsev

Cecconi

Guda

et al. 2015

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Rational development of efficient photo-catalytic systems for hydrogen production requires understanding the catalytic mechanism and detailed information about the structure of intermediates in the catalytic cycle. We demonstrate how time-resolved X-ray absorption spectroscopy in the microsecond time range can be used to identify such intermediates and to determine their local geometric structure. This method was used to obtain the solution structure of the Co(I) intermediate of cobaloxime, which is a non-noble metal catalyst for solar hydrogen production from water. Distances between cobalt and nearest ligands including two solvent molecules and displacement of the cobalt atom out of plane formed by the planar ligands have been determined. Combining in situ X-ray absorption and UV-visible data, we demonstrate how slight modification of the catalyst structure can lead to the formation of a catalytically inactive Co(I) state under similar conditions. Possible deactivation mechanisms are discussed. KeywordsTransient X-ray absorption; photocatalysis; XANES; X-ray absorption spectroscopy; solar fuel Light-driven catalytic systems for hydrogen evolution from water are crucial components of our energy future.[1,2] Efficient photo-catalytic hydrogen evolution systems contain platinum nanoparticles or other noble metals that are expensive and of limited availability. This has triggered the development of catalysts based on earth-abundant 3d elements, such as cobalt, iron and nickel. [3][4][5][6][7][8] Cobaloximes are perspective and popular hydrogen evolving molecular catalysts [7][8][9] and they have been implemented in many homogeneous multicomponent photocatalytic systems. [7,[10][11][12][13][14][15][16] (Fig. 1, top panel). In the absence of a sacrificial electron donor, charge recombination returns the system to its initial state. The solution structure of the Co(I) intermediate has been predicted using DFT, [17,20,22] but was never experimentally probed. A crystal structure of the Co(I) derivative [Co(dpgBF 2 ) 2 (CH 3 CN)] -has been reported, [18] but the structure of the intermediate in solution can be significantly different from those in the solid phase. Here, we combine in situ time-resolved X-ray absorption near edge structure (XANES) spectroscopy and UV-visible spectroscopy to investigate the early stages of hydrogen evolution mediated by Co1 and Co2 catalysts. We report the first experimental determination of the structure of the Co(I) intermediate formed from Co2 in solution and highlight a major difference in terms of reactivity and stability between Co2 and Co1 under photo-catalytic conditions.XANES spectra contain element-specific information about the structure of metal complexes.[23-25] Time-resolved X-ray absorption spectroscopy in the laser pump-X-ray probe mode was initially established for experiments in the picosecond -nanosecond time range [26,27]. We recently extended the technique to the microsecond range (pumpsequential-probes[28] and pump-flow-probe[29] methods, see SI). These new...

show abstract

Efficient H2-producing photocatalytic systems based on cyclometalated iridium- and tricarbonylrhenium-diimine photosensitizers and cobaloxime catalysts

Cited by 233 publications

References 17 publications

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

Hydrogen Production by Photoreforming of Renewable Substrates

Microsecond X‐ray Absorption Spectroscopy Identification of Co^I Intermediates in Cobaloxime‐Catalyzed Hydrogen Evolution

Contact Info

Product

Resources

About

Efficient H2-producing photocatalytic systems based on cyclometalated iridium- and tricarbonylrhenium-diimine photosensitizers and cobaloxime catalysts

Cited by 233 publications

References 17 publications

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

Hydrogen Production by Photoreforming of Renewable Substrates

Microsecond X‐ray Absorption Spectroscopy Identification of CoI Intermediates in Cobaloxime‐Catalyzed Hydrogen Evolution

Contact Info

Product

Resources

About

Microsecond X‐ray Absorption Spectroscopy Identification of Co^I Intermediates in Cobaloxime‐Catalyzed Hydrogen Evolution