Welcome to the Institute of Solar Fuels

At the Institute for Solar Fuels we develop new materials and devices for the production of chemical fuels from cheap and abundant resources, such as water and CO2, using sunlight. Our current efforts are focused on photo-electrochemical water splitting. Towards this end, we develop deposition processes and synthesis routes for thin film and nanostructured semiconductors and catalysts, and we investigate the fundamental processes of charge generation, separation, and transfer in the bulk and at the interfaces of these materials. Of particular interest is the role of defects, which we aim to control by developing thermal treatments, passivation layers, and doping strategies. Our experimental toolbox includes a range of thin film deposition techniques, electrochemistry and photo-electrochemistry, time-resolved spectroscopy on fs – s time scales, and synchrotron-based methods under operando conditions.

News and Recent Publications

Hydrogen treatment extends charge carrier lifetime in metal oxide photoelectrodes

Photoelectrodes based on metal oxides have only shown relatively low efficiency, due to poor carrier transport properties and a large concentration of point defects that may act as performance killers. By treating the material at moderate temperatures (300°C) in a hydrogen atmosphere, the photoactivity can be significantly improved. Together with our collaborators, we showed that hydrogen goes into the BiVO4 lattice, where it passivates defects and increases the carrier lifetime by more than a factor of two.

 

J.W. Jang, D. Friedrich, Ss Müller, M. Lamers, H. Hempel, S. Lardhi, Z. Cao, M. Harb, L. Cavallo, R. Heller, R. Eichberger, R. van de Krol, and F. F. Abdi*, Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment”, Adv. Energy Materals, 1701536 (2017)

 

Read press release at HZB website here

Operando study of light-induced reactions at BiVO4 surface

JPCB_highlights

We investigated light-induced modifications of the BiVO4/electrolyte interface. A BiVO4 sample was kept in contact with a phosphate buffer solution while the interface was probed using AP-HAXPES. Measurements were performed at open circuit potential, under dark and light conditions (1 Sun). We find that under illumination bismuth phosphate forms on the BiVO4 surface leading to an increase in negative charge and a re-distribution of the aqueous ions near the interface. The bismuth phosphate layer may act to passivate surface states observed in complementary photoelectrochemical measurements. Finally, we find that such changes are reversible upon returning to dark conditions.

 

M. Favaro,* F. F. Abdi, M. Lamers, E. J. Crumlin, Z. Liu, R. van de Krol, D. E. Starr*, “Light-induced Surface Reactions at the Bismuth Vanadate/Potassium Phosphate Interface”, J. Phys. Chem. B, (accepted, 2017)

High oxygen evolution activities for electrodeposited α-Mn2O3 films

The generation of hydrogen by solar-driven electrochemical water splitting is a possible approach to store renewable energies as a non-fossil fuel in large quantities. To achieve this goal, earth-abundant and highly active catalysts for both half reactions, the hydrogen and the oxygen evolution reaction (OER), have to be identified and developed for a mass market. This kind of catalysts should be applicable in photoelectrochemical water splitting devices, by being deposited as co-catalysts on the surface of suitable photoelectrodes.
Under this aspect, highly porous manganese(III) oxide layers have been developed as OER electrodes showing low over voltages (340mV at 10mA/cm2 current density).

 

M. Kölbach, S. Fiechter, R. van de Krol, P. Bogdanoff, "Evaluation of electrodeposited α-Mn2O3 as a catalyst for the oxygen evolution reaction", Catalysis Today, 290, p. 2-9, (2017)