Ultrastable In‐Plane 1T–2H MoS₂ Heterostructures for Enhanced Hydrogen Evolution Reaction

Metallic 1T MoS 2 is highly desirable for catalyzing electrochemical hydrogen production from water owing to its high electrical conductivity. However, stable 1T MoS 2 is difficult to be produced in large‐scale by either common chemical or physical approaches. Here, ultrastable in‐plane 1T–2H MoS 2 heterostructures are achieved via a simple one‐pot annealing treatment of 2H MoS 2 bulk under a mixture gas of Ar and phosphorous vapor, where phosphorus cannot only occupy the interspace of MoS 2 bulk, resulting in the expansion of MoS 2, but also embed into the lattice of MoS 2, inducing the partial phase transition from 2H to 1T phases of MoS 2 . Benefiting from its significantly improved electrical conductivity, highly exposed active sites, and hydrophily property, in‐plane 1T–2H MoS 2 heterostructures exhibit largely improved electrocatalytic properties for hydrogen evolution reaction (HER) in alkaline electrolytes.