A Si–O–Si bridge assembled from 3-mercaptopropyltrimethoxysilane and silicon carbide for effective charge transfer in photocatalysis

This work demonstrates the functionalization of SiC with the organosilane 3-mercaptopropyltrimethoxysilane via a wet chemical process. The attachment of the covalently bound organosilane onto SiC was indicated by scanning electron microscopy, water contact angle measurements, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. A Si–O–Si bridge was successfully established on the heterogeneous interface, which acts as a fluent carrier transfer channel and can effectively contribute to the quick transfer of photogenerated electrons from the SiC interior to the surface, thus increasing the number of surface active sites and prolonging the charge-carrier lifetime. The photocatalytic H₂ production rate under visible light irradiation was improved to 27.5 μmol h⁻¹ g⁻¹, while unmodified SiC resulted in no H₂ production under the same conditions. The study definitively shows that the Si–O–Si bridge modelled by organosilanes can directly lead to the observed enhanced rate and pave the way for the heterojunction construction of inorganic and organic materials.