Understanding Correlation between Magnetism and Electrocatalytic Hydrogen Evolution Based on Intrinsic Properties of Single MoS₂ Entity

Few-layered molybdenum chalcogenide (MoS2)has attractedconsiderable attention due to its defect-rich structure and activeedge sites, triggering distinctive electrocatalysis and magnetismproperties. Quantifying the intrinsic properties of a single entityis of paramount importance for clarifying the structure-activitycorrelation. Here, the intrinsic activities of single MoS2 flakes toward the hydrogen evolution reaction (HER) were investigatedby single nanoparticle collision electrochemical measurements withand without a moderate magnetic field. Our results demonstrate thatsingle bilayer MoS2 flakes show the highest HER performanceand the greatest magnetic enhancement among bilayer-, trilayer-, andmultilayer-MoS2 flakes. This is because bilayer MoS2 flakes possess abundantly exposed edge sites and sulfurvacancies, which simultaneously accelerate the reaction kinetics ofHER and increase the ferromagnetism properties. This work gives newinsight into providing specific guidance for the magnetic modulationof few-layered MoS2 and the design of highly effectiveMoS(2)-based electrocatalysts.