Electrocatalytic and photocatalytic water oxidation to dioxygen based on metal complexes

Yamazaki, Hirosato; Shouji, Akinori; Kajita, Masashi; Yagi, Masayuki

doi:10.1016/j.ccr.2010.02.008

Cited by 138 publications

(88 citation statements)

References 88 publications

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“…The (14,11) and (16,12) active spaces were found to be well balanced for the cis-[Ru II (bpy) 2 (H 2 O) 2 ] 2+ and in, in-[(Ru II (trpy)(H 2 O)) 2 ( -bpp)] 3+ species, respectively. For the [Ru II (damp)(bpy) (H 2 O)] 2+ species, three different active spaces were considered, with either 10, 9, or 8 electrons in 8 orbitals corresponding to different ruthenium oxidation states (VI, V, and IV, respectively).…”

Section: Multiconfigurational Calculationsmentioning

confidence: 95%

“…This process generates an aerobic atmosphere and a readily usable carbon pool, both of which are essential to sustaining almost all life on our planet. The formation of molecular oxygen occurs in a membrane-embedded protein, photosystem II (PSII), which catalyzes one of the most thermodynamically demanding reactions in biology: the photoinduced oxidation of water [1][2][3][4][5][6][7][8][9][10][11]. Initially, light energy is transformed into chemical energy, which is used to oxidize water into molecular oxygen, four protons, and four electrons (Equation 12.1).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantum Chemical Characterization of Water Oxidation Catalysts

Miró

Ertem

Gagliardi

et al. 2014

Molecular Water Oxidation Catalysis

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Section: Multiconfigurational Calculationsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Quantum Chemical Characterization of Water Oxidation Catalysts

Miró

Ertem

Gagliardi

et al. 2014

Molecular Water Oxidation Catalysis

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“…The most striking success was recently reported by Sun and co-workers [85], who synthesized a super Ru-complex that catalyses the oxygen evolution reaction at a rate comparable with that of PSII. Given that ruthenium is not an abundant metal, attention has been focused on the design and synthesis of watersplitting catalysts composed of readily available elements such as Mn, Co, Fe [66,67,86]. Remarkable advances were recently achieved by Agapie and co-worker [87] and Christou and co-worker [88] in the synthesis of Mn 3 CaO 4 -clusters (figure 9a,b) geometrically very closely resembling the Mn 4 Ca-cluster of PSII.…”

Section: Hybrid Photocatalysts For Water Oxidation and Oxygen Evolutionmentioning

confidence: 99%

From natural to artificial photosynthesis

Barber

Tran

2013

J. R. Soc. Interface.

328

253

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Demand for energy is projected to increase at least twofold by mid-century relative to the present global consumption because of predicted population and economic growth. This demand could be met, in principle, from fossil energy resources, particularly coal. However, the cumulative nature of carbon dioxide (CO 2 ) emissions demands that stabilizing the atmospheric CO 2 levels to just twice their pre-anthropogenic values by mid-century will be extremely challenging, requiring invention, development and deployment of schemes for carbon-neutral energy production on a scale commensurate with, or larger than, the entire present-day energy supply from all sources combined. Among renewable and exploitable energy resources, nuclear fusion energy or solar energy are by far the largest. However, in both cases, technological breakthroughs are required with nuclear fusion being very difficult, if not impossible on the scale required. On the other hand, 1 h of sunlight falling on our planet is equivalent to all the energy consumed by humans in an entire year. If solar energy is to be a major primary energy source, then it must be stored and despatched on demand to the end user. An especially attractive approach is to store solar energy in the form of chemical bonds as occurs in natural photosynthesis. However, a technology is needed which has a year-round average conversion efficiency significantly higher than currently available by natural photosynthesis so as to reduce land-area requirements and to be independent of food production. Therefore, the scientific challenge is to construct an 'artificial leaf' able to efficiently capture and convert solar energy and then store it in the form of chemical bonds of a high-energy density fuel such as hydrogen while at the same time producing oxygen from water. Realistically, the efficiency target for such a technology must be 10 per cent or better. Here, we review the molecular details of the energy capturing reactions of natural photosynthesis, particularly the water-splitting reaction of photosystem II and the hydrogen-generating reaction of hydrogenases. We then follow on to describe how these two reactions are being mimicked in physico-chemical-based catalytic or electrocatalytic systems with the challenge of creating a large-scale robust and efficient artificial leaf technology.

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“…Significant efforts have been undertaken to improve the activity and stability of homogeneous catalysts, as well as developing new ones [99,100]. The overall process for water splitting can best be described as two half reactions: water reduction [101] and water oxidation [102].…”

Section: Photocatalytic Water Splittingmentioning

confidence: 99%

EPR Spectroscopy as a Tool in Homogeneous Catalysis Research

et al. 2015

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In the context of homogeneous catalysis, openshell systems are often quite challenging to characterize. Nuclear magnetic resonance (NMR) spectroscopy is the most frequently applied tool to characterize organometallic compounds, but NMR spectra are usually broad, difficult to interpret and often futile for the study of paramagnetic compounds. As such, electron paramagnetic resonance (EPR) has proven itself as a useful spectroscopic technique to characterize paramagnetic complexes and reactive intermediates. EPR spectroscopy is a particularly useful tool to investigate their electronic structures, which is fundamental to understand their reactivity. This paper describes some selected examples of studies where EPR spectroscopy has been useful for the characterization of open-shell organometallic complexes. The paper concentrates in particular on systems where EPR spectroscopy has proven useful to understand catalytic reaction mechanisms involving paramagnetic organometallic catalysts. The expediency of EPR spectroscopy in the study of organometallic chemistry and homogenous catalysis is contextualized in the introductory Sect. 1. Section 2 of the review focusses on examples of C-C and C-N bond formation reactions, with an emphasis on catalytic reactions where ligand/substrate non-innocence plays an important role. Both carbon and nitrogen centered radicals have been shown to play an important role in these reactions. A few selected examples of catalytic alcohol oxidation proceeding via related N-centered ligand radicals are included in this section as well. Section 3 covers examples of the use of EPR spectroscopy to study important commercial ethylene oligomerization and polymerization processes. In Sect. 4 the use of EPR spectroscopy to understand the mechanisms of Atom Transfer Radical Polymerization is discussed. While this review focusses predominantly on the application of EPR spectroscopy in mechanistic studies of C-C and C-N bond formation reactions mediated by organometallic catalysts, a few selected examples describing the application of EPR spectroscopy in other catalytic reactions such as water splitting, photo-catalysis, photo-redox-catalysis and related reactions in which metal initiated (free) radical formation plays a role are included as well. EPR spectroscopic investigation in this area of research are dominated by EPR spectroscopic studies in isotropic solution, including spin trapping experiments. These reactions are highlighted in Sect. 5. EPR spectroscopic studies have proven useful to discern the correct oxidation states of the active catalysts and also to determine the effective concentrations of the active species. EPR is definitely a spectroscopic technique that is indispensable in understanding the reactivity of paramagnetic complexes and in conjunction with other advanced techniques such as X-ray absorption spectroscopy and pulsed laser polymerization it will continue to be a very practical tool.

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Electrocatalytic and photocatalytic water oxidation to dioxygen based on metal complexes

Cited by 138 publications

References 88 publications

Quantum Chemical Characterization of Water Oxidation Catalysts

Quantum Chemical Characterization of Water Oxidation Catalysts

From natural to artificial photosynthesis

EPR Spectroscopy as a Tool in Homogeneous Catalysis Research

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