SiC Substrate/Pt Nanoparticle/Graphene Nanosheet Composite Photocatalysts for Hydrogen Generation

Abstract

As a widely known semiconductor material, SiC is expected to be used as a photocatalyst for hydrolysis to produce hydrogen. However, the fast recombination of light-induced carriers restricts its photocatalytic activity. To address this issue, SiC/Pt/graphene composite photocatalysts were prepared using a flash joule heating (FJH) method in seconds, and its efficiency of visible-light photoinduced hydrolysis for hydrogen production was significantly improved. The SiC/Pt/graphene photocatalyst achieved optimal performance with 2.8 wt % graphene and 4.0 wt % Pt loading. The highest hydrogen production rate was 2980 μmol•g −1 •h −1 , which is 175 times higher than that of pristine SiC, setting a record for SiC-based photocatalysts. The increased photocatalytic efficiency was due to the in situ formation of stable heterojunctions among β-SiC, graphene and noble metal platinum (Pt) during the FJH process. The TEM clearly observed the heterojunction interface, and the XPS confirmed a 16% increase in the Si−C bond content. The heterojunctions and Si−C bond can accelerate the transfer of photocatalytically produced carriers, inhibiting the fast recombination. Furthermore, the SiC/Pt/graphene composite photocatalysts maintained 80% of the original performance after three test cycles with a total duration of 12 h, showing remarkable stability. The proposed FJH method will provide more selections for preparing highly efficient and stable composite photocatalysts.