Activation of silicon surfaces for H₂ evolution by electrografting of pyridine molecules

In this work we describe an electrografting procedure for the preparation of pyridine-functionalized Si(111) surfaces, and we demonstrate that this modified surface reduces the overpotential for the hydrogen evolution reaction by about 400 mV compared to the H-terminated Si surface. Thus, evidence is presented that the functionalized Si surface has a catalytic activity for an inner sphere electrochemical reaction and might be an attractive alternative to metal or metal oxide cluster-covered semiconductors in photoelectrochemical devices converting solar energy into chemical energy.