报告题目：Efficient Artificial Photosynthesis Based on Earth Abundant Materials
清华大学一等奖学金获得者，国家优秀留学生奖学金获得者。担任《Energy & Environ. Sci.》等二十多份国际刊物的特约审稿人，被《Solar Energy Materials and Solar Cells》、《Solar Energy》等期刊评为年度十大优秀审稿人之一，《Jacobs Journal of Hydrology》期刊编辑。
The world-wide total installed photovoltaic (PV) power is growing so fast that within the end of this decade the electricity generated by solar energy is in the same order as hydro- and nuclear electricity. In combination with the seasonable fluctuations of solar power, this poses enormous technological challenges on the electricity grid and its storage capacity. Finding a cheap technology to store solar energy becomes, much faster than everybody is realizing, the crucial issue for a further successful introduction of solar energy technologies in to our energy infrastructure. In this contribution, we look at the conventional silicon based PV technologies and their opportunities in solar fuel technologies.
Current state-of-the-art system components, like silicon PV modules and electrolyzers, can achieve a solar-to-hydrogen (STH) conversion efficiency of 15%. Alternative approaches, based on photoelectrochemical/photovoltaic (PEC/PV) water splitting, have demonstrated higher STH efficiencies of 15 up to 18% based on III-V semiconductor materials and Platinum electrodes. The problems of these approaches are that they are not cost-effective, the materials are not abundantly available and not resistant against aqueous environment. I present the important role of silicon processing devices and processing technology to tackle these problems.
I demonstrate promising results on silicon based water splitting PEC/PV devices. The light excited charge carriers in photoelectrodes and electrolytes induce oxidation (photoanode) and redox reduction reactions (photocathode) at the electrode /electrolyte interfaces. The over-potential of the photoelectrodes are suppressed by the supplied voltage of the PV devices integrated in to the water splitting device. The cost effective, abundantly available and water resistant silicon can be integrated in both the PEC and PV part of the devices.
I also discuss technical feasibilities and barriers of solar-driven water-splitting systems based on particle slurry reactors with mediators. A particle suspension based reactor using titanium dioxide (TiO2) particles and mediators in aquatic electrolyte is chosen. The realization of reduction of water to hydrogen by oxidizing the bromide ions (Br-) into bromide (Br2), and the oxidation of water to oxygen by reducing the Fe3+ into Fe2+ ions is presented. As a result, the illuminated water is effectively split into hydrogen (H2) and oxygen (O2) in different baggies without the requirement of further separation.