Leading solar fuels research since 1994
 

Welcome!

The Swedish Consortium for Artificial Photosynthesis is a collaborative research environment with the purpose of advancing the science and utilization of solar fuels - fuel from solar energy. We bring together leading scientists with expertise in molecular biology, biophysics and biochemistry, synthetic chemistry and chemical physics.

The Consortium was started in 1994. Since then we have assembled the necessary expertise in an integrated research body, known as the Swedish Consortium for Artificial Photosynthesis.

Here we present who we are and what is going on in our research. We invite anyone who wants to know more about artificial photosynthesis and solar fuels to follow the links to the homepages of our researchers.  

Welcome!

 News

July 16: Tianfei Liu, Meiyuan Guo, Andreas Orthaber, Reiner Lomoth, Marcus Lundberg, Sascha Ott  and  Leif Hammarström  published an article in Nature Chemistry:

Accelerating proton-coupled electron transfer of metal hydrides in catalyst model reactions.

Abstract:

Metal hydrides are key intermediates in catalytic proton reduction and dihydrogen oxidation. There is currently much interest in appending proton relays near the metal centre to accelerate catalysis by proton-coupled electron transfer (PCET). However, the elementary PCET steps and the role of the proton relays are still poorly understood, and direct kinetic studies of these processes are scarce. Here, we report a series of tungsten hydride complexes as proxy catalysts, with covalently attached pyridyl groups as proton acceptors. The rate of their PCET reaction with external oxidants is increased by several orders of magnitude compared to that of the analogous systems with external pyridine on account of facilitated proton transfer. Moreover, the mechanism of the PCET reaction is altered by the appended bases. A unique feature is that the reaction can be tuned to follow three distinct PCET mechanisms—electron-first, proton-first or a concerted reaction—with very different sensitivities to oxidant and base strength. Such knowledge is crucial for rational improvements of solar fuel catalysts.

June 14: Melina Gilbert Gatty,  Sonja Pullen,  Esmaeil Sheibani,  Haining Tian,  Sascha Ott and  Leif Hammarström  published an article in Chemical Science:

Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy. 

Abstract:

Co-sensitization of molecular dyes and catalysts on semiconductor surfaces is a promising strategy to build photoelectrodes for solar fuel production. In such a photoelectrode, understanding the charge transfer reactions between the molecular dye, catalyst and semiconductor material is key to guide further improvement of their photocatalytic performance. Herein, femtosecond mid-infrared transient absorption spectroscopy is used, for the first time, to probe charge transfer reactions leading to catalyst reduction on co-sensitized nickel oxide (NiO) photocathodes. The NiO films were co-sensitized with a molecular dye and a proton reducing catalyst from the family of [FeFe](bdt)(CO)6 (bdt = benzene-1,2-dithiolate) complexes. Two dyes were used: an organic push–pull dye denoted E2 with a triarylamine–oligothiophene–dicyanovinyl structure and a coumarin 343 dye. Upon photo-excitation of the dye, a clear spectroscopic signature of the reduced catalyst is observed a few picoseconds after excitation in all co-sensitized NiO films. However, kinetic analysis of the transient absorption signals of the dye and reduced catalyst reveal important mechanistic differences in the first reduction of the catalyst depending on the co-sensitized molecular dye (E2 or C343). While catalyst reduction is preceded by hole injection in NiO in C343-sensitized NiO films, the singly reduced catalyst is formed by direct electron transfer from the excited dye E2* to the catalyst in E2-sensitized NiO films. This change in mechanism also impacts the lifetime of the reduced catalyst, which is only ca. 50 ps in E2-sensitized NiO films but is >5 ns in C343-sensitized NiO films. Finally, the implication of this mechanistic study for the development of better co-sensitized photocathodes is discussed.

Participants in the CAP workshop in Sigtuna, Sweden, April 26-27, 2018.













Participants in the CAP workshop in Sigtuna, Sweden, April 26-27, 2018.


Last updated August 22 2018