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

Abstract

An Ag2S@MoS2 core–shell nanowire heterojunction, facilely synthesized by simultaneous sulfuration of Ag nanowires (NMs) and growth of MoS2, is used as a model system to disclose how the surface and interface structures influence the photocatalytic activity. The Ag2S@MoS2 NWs with different loading amounts of MoS2 are used as photocatalysts for H2 production. It is found that the highest photocatalytic activity is realized by a moderate loading amount of MoS2. A lower loading amount of MoS2 not only reduces the interfacial contact for insufficient electron–hole separation but also decreases the number of catalytic active sites for H2 production, while a higher loading amount of MoS2 increases the light‐shielding effect of Ag2S and extends the distance of electron transfer to the catalytic active sites for H2 production. Furthermore, with the same loading amount of MoS2, Ag2S@MoS2 NWs also exhibit superior H2 production activity in comparison with pre‐Ag2S@MoS2 NWs with MoS2 grown on pre‐synthesized Ag2S nanowires. The proposed reason is that the simultaneous sulfuration of Ag nanowires and growth of MoS2 results in an intimate contact between Ag2S and MoS2 for smooth interfacial charge transfer, while the two‐step synthetic method leads to a lower quality of the MoS2‐Ag2S 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.

SiNW/C@Pt Arrays for High-Efficiency Counter Electrodes in Dye-Sensitized Solar Cells

“…Bai et al synthesized Ag 2 S@MoS 2 core-shell nanowires with different loadings of MoS 2 to be used in producing hydrogen via photocatalysis. This material exhibited the highest H 2 production rate with a moderate loading of MoS 2 [16]. Likewise, the above-mentioned applications are good examples that nanowires' key feature of a large surface area grants them the desired performance characteristics.…”

Ni-based photocatalytic H2-production cocatalysts2

“…Apart from QDs, hybrids of 1D semiconductor nano-rods/nanowires and Ni-based cocatalysts have been extensively constructed and applied in photocatalytic H2 production. In general, the unique 1D semiconductor nanostructures possess several favorable features, including high accessible surface area, preferential electrical transport in the axial direction, and small transport distance in the radial direction, for improving the separation and transfer of photogenerated charge carriers from the semiconductor to the cocatalyst, thus achieving improved overall photoactivity [10,27,[435][436][437][438][439]. For instance, Sun et al synthesized crystalline Ni2P cocatalysts to modify CdS nanorods for photocatalytic water splitting leading to H2 evolution [329].…”

Unraveling Photoexcited Charge Transfer Pathway and Process of CdS/Graphene Nanoribbon Composites toward Visible‐Light Photocatalytic Hydrogen Evolution

“…Solar‐driven hydrogen production from water has been identified as one of environmentally friendly strategies to tackle grand challenges like energy shortage and environment pollution . Since Fujishima and Honda first reported TiO 2 photoelectrochemical water splitting in 1972, the past decades have seen a significant rise in solar‐driven water splitting .…”