Phase‐Controlled Synthesis of 1T‐MoSe₂/NiSe Heterostructure Nanowire Arrays via Electronic Injection for Synergistically Enhanced Hydrogen Evolution

Abstract The crystal phase significantly affects the properties and functions of molybdenum dichalcogenides (MoX 2 ). Phase‐engineered synthesis is challenging for constructing metallic‐phase 1T‐MoX 2 for better electrocatalysis than their semiconducting counterparts. Here, 1T‐MoSe 2 nanosheet arrays are successfully prepared on metallic NiSe nanowires to couple the synergistic effects of efficient hydrogen formation and water dissociation for hydrogen evolution reaction (HER). Systematic investigations reveal that the electronic injection from NiSe to MoSe 2 induces the phase transition from 2H‐ to metallic 1T‐phase. Benefiting from the phase engineering for enhancing intrinsic activity, the heterostructure for synergistically boosting water dissociation—as well as hierarchical 3D catalyst configuration for abundant active sites, efficient electron transport and mass transfer—the obtained shell/core 1T‐MoSe 2 /NiSe exhibits superior HER activity and durability. Such a strategy paves a new way for fabricating various 1T‐MoX 2 ‐based heterostructures for diverse applications.