Colloidal semiconductors in systems for the sacrificial photolysis of water: sensitization of titanium dioxide by adsorption of ruthenium complexes

Furlong, D. Neil; Wells, D.; Sasse, W. H. F.

doi:10.1021/j100278a029

Cited by 88 publications

(81 citation statements)

References 2 publications

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“…As a result, this trimer is likely to be adsorbed in a flat configuration. The surface area occupied by 2 is comparable to that for the complex RuL, [14] which has been determined as 100 A'lmolecule.…”

Section: Preparation Of Tio Sols In Etohmentioning

confidence: 70%

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO₂ Films

Nazeeruddin

Liska

Moser

et al. 1990

Helvetica Chimica Acta

210

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A series of CN-bridged trinuclear Ru complexes of the general structure [RuL2(J-(CN)Ru(CN)L2),1 where L is 2,2'-bipyridine-4,4'-dicarboxylic acid and L is 2,2'-bipyridine (1) 2,2'-bipyridine-4,4'-dicarboxylic acid (2), 4,4-dimethyl-2,2'-bipyridine (3), 4,4'-diphenyL2,2'-bipyridine (4), 1,lO-phenanthroline (5), and bathophenanthrolinedisulfonic acid (6) have been synthesized, and their spectral and electrochemical properties investigated. The two carboxylic functions on the 2,2'-bipyridine ligand L serve as interlocking groups through which the dye is attached at the surface of Ti02 films having a specific surface texture. The role of these interlocking groups is to provide strong electronic coupling between the A * orbital of the 2,2'-bipyridine and the 3d-wave-function manifold of the conduction band of the TiOz, allowing the charge injection to proceed at quantum yields close to 100%. The charge injection and recombination dynamics have been studied with colloidal TiOz, using laser photolysis technique in conjunction with time-resolved optical spectroscopy. Photocurrent action spectra obtained from photo-electrochemical experiments with these trinuclear complexes cover a very broad range in the visible, making them attractive candidates for solar light harvesting. Monochromatic incident photon-to-current conversion efficiencies are strikingly high exceeding 80% in some cases. Performance characteristics of regenerative cells operating with these trinuclear complexes and ethanolic triiodide/iodide redox electrolyte have been investigated. Optimal results were obtained with complex 1 which gave a fill factor of 75 % and a power conversion eficiency of 11.3%at520nm.Introduction. -The worldwide quest to develop clean and renewable energy resources has stimulated a major effort in the field of photovoltaic cells. Apart from the conventional dry cells based mostly on silicon technology, electricity can be produced from sunlight also by photo-electrochemical devices [I]. These studies have mainly employed single-crystal semiconductors as light harvesting units whose price is prohibitively high for practical development. One alternative and much cheaper approach is to make use of dye-sensitized, large band-gap semiconductor films to absorb solar light [2]. In such a device, a dye stuff (sensitizer) absorbs visible light and, after excitation, injects electrons in the conduction band of the semiconductor producing an electric current. The difficulties in obtaining reasonable conversion efficiencies with such systems are notorious. Apart from poor injection quantum yields, the light absorption by a monolayer of sensitizer adsorbed on a flat surface is at best a few percent. Multilayer deposition has proved to be an unsuccessful approach to solve this dilemma due to the lack of photoactivity and the filtering effect of the dye molecules which are not in direct contact with the semiconductor.A recent unexpected breakthrough in this field is the discovery [3--81 that TiO, films with a specific fractal-type surface texture ...

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Section: Preparation Of Tio Sols In Etohmentioning

confidence: 70%

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO₂ Films

Nazeeruddin

Liska

Moser

et al. 1990

Helvetica Chimica Acta

210

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“…The sacrificial electron donors used in these studies depended on system pH and were generally based on compounds having tertiary amine functionality for decomposition following oxidation, such as triethylamine (TEA), triethanolamine (TEOA), and ethylenediamine-N,N, N′,N′-tetraacetic acid (EDTA) (17, 19-22). A different electron mediator during the early studies on light-driven generation of hydrogen was found to be TiO 2 , which when platinized served as both the mediator and the catalyst (25)(26)(27)(28).During the more than three decades that have passed since the initial reports (17,(19)(20)(21)(22)(25)(26)(27), every aspect and component of photochemical proton reduction systems have been investigated with the goal of increasing activity and durability. These include new molecular catalysts and different photosensitizers ranging from other metal complexes with long-lived charge-transfer excited states to strongly absorbing organic dyes.…”

mentioning

confidence: 99%

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Das

Han

Haghighi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

130

139

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Unique tripodal S-donor capping agents with an attached carboxylate are found to bind tightly to the surface of CdSe nanocrystals (NCs), making the latter water soluble. Unlike that in similarly solubilized CdSe NCs with one-sulfur or two-sulfur capping agents, dissociation from the NC surface is greatly reduced. The impact of this behavior is seen in the photochemical generation of H 2 in which the CdSe NCs function as the light absorber with metal complexes in aqueous solution as the H 2 -forming catalyst and ascorbic acid as the electron donor source. This precious-metalfree system for H 2 generation from water using [Co(bdt) 2 ]− (bdt, benzene-1,2-dithiolate) as the catalyst exhibits excellent activity with a quantum yield for H 2 formation of 24% at 520 nm light and durability with >300,000 turnovers relative to catalyst in 60 h.photochemistry | solar energy | catalysis | water splitting | quantum dots A rtificial photosynthesis (AP) represents an important strategy for energy conversion from sunlight to storage in chemical bonds (1-4). Unlike natural photosynthesis in which CO 2 + H 2 O are converted into carbohydrates and O 2 , the key energy-storing reaction in AP is the splitting of water into its constituent elements of hydrogen and oxygen (5-16). As a redox reaction, water splitting can be divided into two half-reactions, of which the light-driven generation of H 2 is the reductive component. Many systems for the photogeneration of H 2 have been described over the years and they typically consist of a light absorber, a catalyst for H 2 formation, and sources of protons and electrons. For systems that function in aqueous media, the protons are provided by water, whereas for nonaqueous systems, the protons are provided by weak, generally organic acids. The source of electrons in these photochemical systems is generally a sacrificial electron donor-that is, a compound that decomposes following one electron oxidation.Reports of the light-driven generation of hydrogen date back more than 30 y, beginning with a multicomponent system containing [Ru(bpy) 3 ] 2+ (where bpy is 2,2′-bipyridine) as the chromophore or photosensitizer (PS) and colloidal Pt as the catalyst for making H 2 from protons and electrons (17). In these and many subsequent systems, electron mediators were used to accept an electron from the excited chromophore, PS*-thereby serving as an oxidative quencher-and transfer it to the catalyst. Whereas two of the initial mediators were bpy complexes of rhodium and cobalt (17, 18), the overwhelming majority of electron mediators in these systems were dialkylated 2,2′-and 4,4′-bipyridines and their derivatives (19)(20)(21)(22). The most extensively used of these mediators was methyl viologen (MV 2+ , dimethyl-4,4′-bipyridinium, usually as its chloride salt). These mediators were subsequently found to undergo deactivation in their role by hydrogenation (23, 24). The sacrificial electron donors used in these studies depended on system pH and were generally based on compounds having tertiary amine func...

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“…Carboxyl [49][50][51][52] and phosphonate [53][54][55] are the two most important terminal groups of Ru-complexes that have been studied. Choi's team has studied the photocatalytic activity of semiconductors using Ru-complexes with various terminal groups.…”

Section: An Overview Of Dyes As Photosensitizersmentioning

confidence: 99%

“…Electron donors are required for dye regeneration to pursue a continuous hydrogen generation scheme. Different compounds such as acetonitrile [76], methanol [77][78][79], Na2S-Na2SO3 [80,81], EDTA [49], and TEOA are reported as electron donors.…”

Section: An Overview Of Sacrificial Agentsmentioning

confidence: 99%

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Dye-Sensitized Photocatalytic Water Splitting and Sacrificial Hydrogen Generation: Current Status and Future Prospects

2017

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Today, global warming and green energy are important topics of discussion for every intellectual gathering all over the world. The only sustainable solution to these problems is the use of solar energy and storing it as hydrogen fuel. Photocatalytic and photo-electrochemical water splitting and sacrificial hydrogen generation show a promise for future energy generation from renewable water and sunlight. This article mainly reviews the current research progress on photocatalytic and photo-electrochemical systems focusing on dye-sensitized overall water splitting and sacrificial hydrogen generation. An overview of significant parameters including dyes, sacrificial agents, modified photocatalysts and co-catalysts are provided. Also, the significance of statistical analysis as an effective tool for a systematic investigation of the effects of different factors and their interactions are explained. Finally, different photocatalytic reactor configurations that are currently in use for water splitting application in laboratory and large scale are discussed.

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Colloidal semiconductors in systems for the sacrificial photolysis of water: sensitization of titanium dioxide by adsorption of ruthenium complexes

Cited by 88 publications

References 2 publications

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO₂ Films

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO₂ Films

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Dye-Sensitized Photocatalytic Water Splitting and Sacrificial Hydrogen Generation: Current Status and Future Prospects

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Colloidal semiconductors in systems for the sacrificial photolysis of water: sensitization of titanium dioxide by adsorption of ruthenium complexes

Cited by 88 publications

References 2 publications

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO2 Films

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO2 Films

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Dye-Sensitized Photocatalytic Water Splitting and Sacrificial Hydrogen Generation: Current Status and Future Prospects

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Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO₂ Films

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO₂ Films