On the basis of a simple ion exchange method, a MoS2/g-C3N4/graphene oxide (GO) ternary nanojunction was constructed as an efficient photocatalyst for hydrogen evolution using solar energy. The confinement effect in MoS2 and g-C3N4 quantum dots enhances their water-splitting redox activities. The designed heterostructure featured a band alignment that facilitates the collection of electrons in MoS2 and holes in g-C3N4, effectively suppressing the recombination of photogenerated charge carriers. Furthermore, the GO with high specific surface area serves as an excellent conductive substrate to transport holes speedily. This study thus provides a novel and facile route of establishing efficient composite photocatalyst with multinary components for energy conversion.

In this article, a novel AgS nanoparticle-decorated MoS composite (A@M) was synthesized through a facile in situ growth of the monoclinic crystallographic AgS on MoS nanosheets. The A@M composite was used as a catalyst in water splitting which exhibits higher electrocatalytic and photoelectrocatalytic activity than the respective pure MoS and AgS counterparts. Experimental results indicate that the as-prepared A@M composite with an optimal AgS/MoS molar ratio of 16.30% (16%A@M) shows the best catalytic performance with low overpotentials (110 mV for V, 190 mV for onset overpotential, 208 mV for the current density of 20 mA cm), a small Tafel slope (42 mV dec), and a high photocurrent (82 μA cm under an applied potential of 0.4 V). The enhanced electrocatalytic activity is associated with the improved electrical conductivity resulting from the stretched MoS nanosheets and the enriched active sites due to the decorated AgS particles. The formation of a type II heterojunction structure at the interface between AgS and MoS facilitates the separation of photogenerated charge carriers, and thus is responsible for the enhanced photoelectrocatalytic activity and photocatalytic H production rate (628 μmol h g). This work suggests a promising choice to overcome the intrinsic drawbacks of MoS nanostructures for the application in hydrogen evolution.