Tungsten-Modulated Molybdenum Selenide/Graphene Heterostructure as an Advanced Electrode for All-Solid-State...

Transition metal dichalcogenides (TMDs) have attracted widespread attention due to their excellent electrochemical and catalytic properties. In this work, a tungsten (W)-modulated molybdenum selenide (MoSe₂)/graphene heterostructure was investigated for application in electrochemistry. MoSe₂/graphene heterojunctions with low-doped W compositions were synthesized by a one-step hydrothermal catalysis approach. Based on the conducted density functional theory (DFT) calculations, it was determined that inserting a small amount of W (≈5%) into the MoSe₂/graphene heterostructure resulted in the modification of its lattice structure. Additionally, an increase in the distance between layers (≈8%) and a decrease in the adsorption energy of the potassium ions (K⁺) (≈-1.08 eV) were observed following W doping. Overall, the electrochemical performance of the MoSe₂/graphene hybrid was enhanced by the presence of W. An all-solid-state supercapacitor device prepared using electrodes based on the W-doped MoSe₂/graphene composite achieved excellent capacitance of 444.4 mF cm^-2 at 1 mV s^-1. The results obtained herein revealed that the MoSe₂/graphene hybrid exhibiting low W composition could be valuable in the field of energy storage and isoelectronic doping of TMDs.