1T‐MoS ₂ Enriched Hierarchical MoS ₂ /MoO ₃ Produced by Phase Transformation for Efficient Hydrogen Evolution Reaction

Abstract In recent years, transition metal sulfides have been widely studied in the context of their use as electrocatalysts. The electrocatalytic propensity of the classical semiconductor MoS 2 , which exists in the 1T and 2H phase structures, has attracted extensive attention. Therefore, the synthesis of highly active and stable MoS 2 ‐based catalysts has become the goal of many research efforts. We recently developed a method that can be utilized to prepare the MoS 2 /MoO 3 heterojunction in a phase‐controlled manner. 1T‐MoS 2 phase enriched MoS 2 /MoO 3 heterojunction can be generated using a simple hydrothermal and acid treatment sequence and that the heterojunction has a unique three‐dimensional structure, large active surface area, and therefore achieve a low overpotential and high catalytic current density, as well as long‐term stability for the hydrogen evolution reaction.