Properties of Electrodeposited Molybdenum Disulfide on Zinc Oxide and Zinc Oxide/Zinc Sulfide Nanowires

Abstract Molybdenum sulfide (MoS 2 ) has attracted significant attention as a non-platinum group electrocatalyst for the hydrogen evolution reaction (HER). Due to the increased activity of the edge sites relative to the basal plane, significant efforts have been made to increase the density of those catalytically active edge sites. This work aims to take advantage of this phenomenon while also coupling it with band engineering through the synthesis of heterostructures, namely that between ZnO, ZnS, and MoS 2 . Here, we report on a variety of ZnO-based nanowires that have been functionalized with MoS 2 species and discuss their catalytic efficacy in both acidic and alkaline conditions. In acidic conditions, both ZnO-MoS 2 and ZnO-ZnS-MoS 2 demonstrated an increase in catalytic activity over their constituents, requiring 181 mV and 154 mV, respectively, to reach 10 mA/cm 2 . In alkaline conditions, the ZnO-ZnS-MoS 2 structure also demonstrated an increase, requiring only 209 mV to reach 10 mA/cm 2 . This has been attributed primarily to the synergistic properties of the band alignment structure and the increased surface area afforded by the nanowire structure. Overall, the synthesized nanowire heterostructures were found to be high performing and give insight into how the changing band alignment and morphology can play a significant role in increasing the catalytic performance towards HER.