Earth receives an overabundance of green energy from the sun, but currently our ability to harness this power is limited by our technology and the intermittency of the sunlight. To combat the effects of climate change, renewable technological breakthroughs are needed to produce solar fuels such as hydrogen gas at a commercialized level. One strategy to achieve this goal stems from developing a better understanding of molecular catalyst-light absorbing material interfaces. Insight into the performance and decomposition of these devices can be utilized the design of more stable, efficient, and cost-effective systems for solar energy conversion. Herein, an iron based synthetic analogue of the active site of the hydrogenase enzyme, Fe2(CO)6(µ-S-C6H4-p-OH)2, selected for its low cost and facile synthesis, was employed as a hydrogen evolving catalyst. In order to utilize solar energy the molecular catalyst was covalently bound to a light absorbing silicon (100) substrate, due to its favorable light-absorption properties and earth abundancy. This hybrid system shifted the onset potential a 100 mV more positive and passivated the surface from slowly forming a native oxide layer in atmospheric conditions over a period of 300 hours. After an hour of electrolysis at -1.4V vs Ag/AgCl the molecular catalyst was found to decompose at the active center rather than the linkage group in between the catalyst and silicon substrate. With heightened understanding of the molecular catalyst decomposition, current synthetic efforts are underway to improve stability under prolonged electrochemical conditions.

Hydrogen evolution at a hybrid organometallic catalyst-silicon interface and the decomposition of the interface

2019 Fall National Meeting

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