1. Development of complex photoelectrodes for efficient water splitting under visible light irradiation (PhD thesis Rochan Sinha)

The aim of the project is to unravel the rate limiting steps at photo-electrochemical interfaces. For this, we fabricate and characterize well-defined, complex photo-electrodes which show stable and efficient photo-electrochemical activity. ‘Complex’ here pertains to both material composition as well as to the micro-/nanostructure. The project is integrated in the frame of combining experiments and modeling & simulations in order to identify the rate limiting steps at photo-electrochemical interfaces.
We are currently focusing on hematite (Fe2O3) based photoelectrodes for oxygen evolution reaction. We change the micro-/nanostructure and the chemistry by the selection of the thin film deposition parameters, annealing parameters, plasma treatment, doping, and the application of under-/ and overlayers.

2. Innovative photoelectrode micro-/nanostructures and 3D structures  (Phd thesis Yihui Zhao)

The active surface area is an important parameter in electrochemistry and catalysis in order to reach high performance of electrodes in energy devices: the more surface area is available, the more reactions can take place and the higher the performance. In this study, we use microstructuring techniques in order to fabricate well-defined photo-electrodes. This allows us to relate geometrical effects with photo-electrochemical properties. The established techniques on microstructuring of metal oxide photoelectrodes will also be used to fabricate new innovative 3D structures for photoelectrodes.


3. Plasma nanostructured photoelectrodes (contact: Anja Bieberle)

In this project we study the feasibility of nanostructuring of thin metal and metal oxide films for possible application as photo-electrodes in solar fuel conversion. The formation of nanofuzz is a known phenomenon in fusion research due to plasma surface interaction caused by high ionic flux of the plasma. While the nanofuzz is not appreciated in fusion studies due to weakening of the walls, the large surface area of the materials is attractive for catalysis and electrochemistry.


4. Density Functional Theory simulations of the Oxygen Evolution Reaction (Post doc Xueqing Zhang)

Identifying the limiting of reaction steps in photo-electrochemical water splitting can help to maximize the performance and efficiency. In this project, we combine experiments and modeling & simulations. We simulate the oxygen evolution reaction (OER) and calculate the overpotentials and rate constants of each reaction step. Simulations are carried out on hematite surfaces with different orientations, surface terminations, and oxygen vacancy concentrations. The data will be used as input for the state-space modeling approach to simulate experimental photo-electrochemical data, such as impedance spectra.