Surface and Interface Engineering in Ag₂S@MoS₂ Core–Shell Nanowire Heterojunctions for Enhanced Visible Photocatalytic Hydrogen Production

Abstract

Abstract An Ag 2 S@MoS 2 core–shell nanowire heterojunction, facilely synthesized by simultaneous sulfuration of Ag nanowires (NMs) and growth of MoS 2 , is used as a model system to disclose how the surface and interface structures influence the photocatalytic activity. The Ag 2 S@MoS 2 NWs with different loading amounts of MoS 2 are used as photocatalysts for H 2 production. It is found that the highest photocatalytic activity is realized by a moderate loading amount of MoS 2 . A lower loading amount of MoS 2 not only reduces the interfacial contact for insufficient electron–hole separation but also decreases the number of catalytic active sites for H 2 production, while a higher loading amount of MoS 2 increases the light‐shielding effect of Ag 2 S and extends the distance of electron transfer to the catalytic active sites for H 2 production. Furthermore, with the same loading amount of MoS 2 , Ag 2 S@MoS 2 NWs also exhibit superior H 2 production activity in comparison with pre ‐Ag 2 S@MoS 2 NWs with MoS 2 grown on pre‐synthesized Ag 2 S nanowires. The proposed reason is that the simultaneous sulfuration of Ag nanowires and growth of MoS 2 results in an intimate contact between Ag 2 S and MoS 2 for smooth interfacial charge transfer, while the two‐step synthetic method leads to a lower quality of the MoS 2 ‐Ag 2 S interface and thus poor interelectron transfer. This work highlights the importance of a rational surface and interface design of semiconductor heterojunctions for realizing high‐performance photocatalytic applications.