Keynote: Integrating Discovery, Direct and Combinatorial Science for Solar Fuels Prototype Development

Photoelectrochemical water splitting has a more than four decade long history [1]. Research and development efforts, however, have been almost exclusively directed to the investigation of suited electrode materials and to the study of interfacial processes such as charge transfer and (photo)corrosion [2]. Half cell performance and characterization has predominantly been the focus [3, 4]. During this incubation period, some basic concepts have been developed [5] and thermodynamic aspects of stability and the basic processes in water oxidation and proton reduction were established [6].

The development of a technological device, comparable to that of the dye sensitized solar cell [7], was hitherto complicated by rather little coordinated research activities, pursued mostly in single investigator teams of limited size. Accordingly, some of the issues in light-induced water splitting, such as photoanode, -cathode and heterogeneous catalyst materials development, details of reaction mechanisms, successful implementation of stabilization strategies and tailored membrane design were delayed.

In this presentation, the strategy of the Joint Center for Artificial Photosynthesis in developing solar fuel prototypes in a field where a corresponding industry does not exist, where the work force has to be trained in photoelectrochemistry and the materials science for the envisaged prototype components and where design criteria for devices have to be developed, will be outlined. Examples for achievements in basic science, component integration and testbed/prototype assembly and characterization will be shown. They encompass (i) an efficient strategy to protect light absorbers against photocorrosion, which allows the use of technologically advanced semiconductors such as III-V compounds, (ii) the increased understanding of traditional and novel electrocatalysts by in operando synchrotron radiation experimentation, (iii) the use of advanced photonics for light management, (iv) combinatorial approaches for catalyst development, (v) modelling, design and realization of solar fuel reactors and (vi) feedback mechanisms for materials and system optimization.  

The interaction and the training of the workforce demands advanced communication technologies and regular cross team and cross disciplinary meetings as well as educational means. An overview of the major communication and education instruments will be given.

1. A. Fujishima, K. Honda, Nature 238 (1972) 37

2. H. Gerischer, Pure and Appl. Chem. 52 (1980) 2649

3. A. Heller, R.G. Vadimsky, Phys. Rev. Lett. 46 (1981) 1153

4. H.J. Lewerenz, C. Heine, K. Skorupska, N. Szabo, T. Hannappel, T. Vo-Dinh, S. A. Campbell, H. W. Klemm and A. G. Muñoz, Energy and Environm. Sci. 3 (2010) 748

5. A. Nozik, Ann. Rev. Phys. Che. 29 (1978) 189

6. B.A. Parkinson, Acc. Chem. Res. 17 (1984) 431

7. M. Graetzel, J. Photochem. Photobiol. C: Photochemistry Reviews 4 (2003) 145