Enhanced Photocatalytic Activity of SiC-Based Ternary Graphene Materials: A DFT Study and the Photocatalytic Mechanism

A graphene-like semiconductor composite is one of the most promising photocatalyst that does not use noble metals. These composites have excellent photocatalytic properties and have attracted great attention for water splitting. Here, a facile method called the hydrothermal method was used to prepare graphene oxide (GO)/SiC/MoS2 composites. Under visible-light irradiation, the GO/SiC/MoS2 composite had excellent photocatalytic production of hydrogen from water splitting. In particular, the catalyst added 8 wt % of Mo weight yielded the highest quantum of 20.45% at 400-700 nm of wavelength. A positive synergistic effect between the layered GO and MoS2 components contributed to the enhanced photoactivity of the SiC particles. The synergistic effect reduced the recombination of photogenerated holes and electrons, enhanced the rate of electron transfer, and provided more reaction active sites for water splitting. The interactions among SiC, GO, and MoS2 were investigated using a density functional theory. The calculations showed that the relative positions between graphene only slightly affect the stability of the interface, and the MoS2 layers have a great influence. The photocatalytic mechanism was also discussed, and electron transfer was predicted.