Ultrathin CdS Nanosheets Grown on N-Doped Carbon Nanotubes with Encapsulated Cobalts for Highly Improved Visible-Light-Driven Hydrogen Production

Cocatalysts in photocatalytic systems play an important role in achieving efficient charge separation. These cocatalysts usually have a small size and are generally anchored onto main catalysts. They are taken as active centers to receive photogenerated electrons for water splitting. However, their high loading concentration usually leads to the degradation of water splitting. Here, we present a different strategy for the design of the main catalyst and cocatalyst. We used small-sized ultrathin cadmium sulfide (CdS) nanosheets as the main catalysts and anchored them onto large-sized N-doped carbon nanotubes with encapsulated cobalts. The photocatalytic hydrogen production of our optimized composite is ∼21.8 mmol/g, ∼3 times higher than that of pure CdS. Mechanism study shows that photoelectrons can be transferred from CdS to N-doped carbon nanotubes, thus achieving fast charge separation and efficient hydrogen production.