scispace - formally typeset
Search or ask a question

Showing papers by "Michael Grätzel published in 1979"


Journal ArticleDOI
01 Oct 1979-Nature
TL;DR: In this article, the first observations of the dynamics of intervention of the Pt particles in the redox events are presented, and a centrifuged colloidal Pt catalyst stabilised by polyvinyl alcohol showed exceptionally high activity in promoting hydrogen evolution from water via 2MV+ + H2O→PtH2 + 2OH− + 2 MV2+ where MV+ stands for reduced methylviologen.
Abstract: Noble metal dispersions are suitable for mediating light-induced hydrogen1–5 and oxygen6–8 evolution from water. We report here a dramatic improvement of the hydrogen production rate when very finely dispersed platinum is used as a mediator in reaction (1). The first observations of the dynamics of intervention of the Pt particles in the redox events are presented. A centrifuged colloidal Pt catalyst stabilised by polyvinyl alcohol showed exceptionally high activity in promoting hydrogen evolution from water via 2MV+ + H2O→PtH2 + 2OH− + 2MV2+ (1) where MV+ stands for reduced methylviologen. The latter is produced photochemically in aqueous solution containing Ru(bipy)32+ as a sensitiser and EDTA as an electron donor. At 10−3 M Pt the reoxidation of MV+ requires only 15 µs and leads to quantitative formation of H2.

228 citations



Journal ArticleDOI
TL;DR: In this paper, a statistical model describing the distribution of solubilizate molecules in micellar systems is developed on the basis of their kinetic interaction with the host aggregates.
Abstract: A statistical model describing the distribution of solubilizate molecules in micellar systems is developed on the basis of their kinetic interaction with the host aggregates. The distribution function obtained corresponds to a Poisson law governing the occupancies of individual micelles by quest molecules. This model provides the basis for the development of a theory which treats the behavior of pyrene fluorescence emission in micellar systems. Solutions of this fluorophore in cetyltrioxyethylene sulfate micelles were examined experimentally both by steady‐state and time‐resolved fluorescence techniques. The results obtained are in excellent agreement with the predictions of the model. From this analysis the rate constant for the intramicellar encounter of two pyrene molecules was derived as ke=9×106 s−1. The aggregation number of CTOES was determined as 96 surfactant molecules/micelle.

131 citations



Journal ArticleDOI
TL;DR: In this article, the optical absorption spectrum of excited ruthenium tris-bipyridyl (Ru(bpy)2+3) in the range of 244-500 nm was determined by applying the method of intensity dependence measurement.

72 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a Web of Science Record created on 2006-02-21, modified on 2017-05-12, for the LPI-ARTICLE-1979-001.
Abstract: Reference LPI-ARTICLE-1979-001doi:10.1002/hlca.19790620738View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

59 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a Web of Science Record created on 2006-02-21, modified on 2017-05-12, for the LPI-ARTICLE-1979-003.

43 citations



Journal ArticleDOI
TL;DR: In this paper, a two-component redox system for H2 production with electron donors was proposed, where the electron donor was a colloidal Pt-redox catalyst sensitized by proflavine.
Abstract: Efficient photoproduction of H2 from water in the presence of electron donors such as ethylenediaminetetra-acetic acid or triethanolamine and a colloidal Pt-redox catalyst, sensitized by proflavine, is reported; this is a two-component redox system for H2 production as against the common three-component systems with an electron acceptor.

29 citations



Journal ArticleDOI
TL;DR: In this paper, cooperative effects assisting charge separation are observed with functional micelles where the redox relays are linked to the surfactant molecule. And the implications for energy conversion systems are discussed.
Abstract: Self-assembly of surfactant molecules in aqueous solution yields micellar aggregates. These, through local polarity and electrostatic potential effects, can be used kinetically to control light-initiated electron transfer reactions. Cooperative effects assisting charge separation are observed with functional micelles where the redox relays are linked to the surfactant molecule. The implications for energy conversion systems are discussed.