Construction of mono- and multimolecular layers with electron transfer mediation function and catalytic activity for hydrogen evolution on a hydrogen-terminated Si(111) surface via Si-C bond

Organic molecular layers with viologen moiety (i.e., electron acceptor) were constructed on a hydrogen-terminated Si(111) surface via a Si-C bond. Electrochemical characteristics after each synthetic process were measured, and electron mediation capability of the viologen moiety was demonstrated. Incorporation of platinum particles on the viologen-modified Si(111) surface was proved to enhance the hydrogen evolution reaction (HER) rate. Further improvement of the HER rate was achieved by the modification with viologen/Pt multilayers. Photoelectrochemical HER at the p-Si(111) electrode was also significantly accelerated by the modification with mono- and multiviologen/Pt layers.