Interfacial engineering of ZnS–ZnO decorated MoS₂ supported on 2D Ti₃C₂T_x MXene sheets for enhanced hydrogen evolution reaction

Molybdenum disulfide (MoS₂) contains inactive basal and edge planes, which hinders its effectiveness in facilitating environmentally clean Hydrogen Evolution Reaction (HER) in electrocatalytic water splitting. Herein, we report a single-step synthesis strategy for developing ZnS–ZnO–MoS₂/Ti₃C₂T_x MXene (ZZM/MX) nanostructures through a hydrothermal approach. The SEM micrographs clearly demonstrate edge plane modification in MoS₂, making them sharper and more exposed outward. XRD analysis exhibited the formation of ZnS and ZnO phases over MoS2 surface which was further supported by XPS analysis. The molar percentage of Zn precursor was increased from 1 % to 6 % and the resultant samples were designated as ZZM/MX-1, ZZM/MX-2, ZZM/MX-4, and ZZM/MX-6, respectively. Among the prepared samples, ZZM/MX-4 electrocatalyst exhibited the least overpotential of 327.6 mV @ 10 mA cm⁻²; and a low Tafel slope of 79.5 mVdec⁻¹ in 0.5 M H₂SO₄ electrolyte for HER. Also, it demonstrated excellent stability, withstanding 50 h of operation under acidic conditions. The higher electrocatalytic performance in this material can be attributed to the robust interaction between hetero-phase interfaces along ZnS–ZnO–MoS₂ and MXene (Ti₃C₂T_x) support, which activates MoS₂ basal planes and enhances the charge transfer properties. Further, the activation of MoS₂ edges by introduction of ZnS/ZnO phases led to enhanced number of active sites for HER electrocatalysis. This work showcases an opportunity to apply dual modification of edge and basal planes in various other chalcogenide materials to enhance environmentally friendly clean HER performance and stability.