Ultrathin MoS₂ layers anchored exfoliated reduced graphene oxide nanosheet hybrid as a highly efficient cocatalyst for CdS nanorods towards enhanced photocatalytic hydrogen production

The development of novel highly efficient noble metal-free co-catalysts for enhanced photocatalytic hydrogen production is of great importance. Herein, we report the synthesis of novel and highly efficient noble metal-free ultra-thin MoS₂ (UM) layers on exfoliated reduced graphene oxide (ERGO) nanosheets as a cocatalyst for CdS nanorods (ERGO/UM/CdS). A simple method different from the usual preparation techniques is used to convert MoS₂ to UM layers, graphene oxide (GO) to ERGO nanosheets, based on ultrasonication in the absence of any external reducing agents. The structure, optical properties, chemical states, and dispersion of MoS₂ and CdS on ERGO are determined using diverse analytical techniques. The photocatalytic activity of as-synthesized ERGO/UM/CdS composites is assessed by the splitting of water to generate H₂ under simulated solar light irradiation in the presence of lactic acid as a hole (h⁺) scavenger. The observed extraordinary hydrogen production rate of ∼234 mmol h⁻¹ g⁻¹ is due to the synergetic effect of the ultrathin MoS₂ layers and ERGO, which leads to the effective separation of photogenerated charge carriers and improves the surface shuttling properties for efficient H₂ production. Furthermore, the observed H₂ evolution rate is much higher than that for individual noble metal (Pt), ERGO and MoS₂-assisted CdS photocatalysts. Moreover, to the best of our knowledge, this is the highest H₂ production rate achieved by a RGO and MoS₂ based CdS photocatalyst for water splitting under solar light irradiation.