Iridium-Triggered Phase Transition of MoS₂ Nanosheets Boosts Overall Water Splitting in Alkaline Media

Metallic phase molybdenum disulfide (1T-MoS2), with its fast carrier mobility and highly abundant active sites, plays a vital role in the field of catalysis. However, the development of a simple and efficient strategy for the preparation of stabilized 1T-MoS2 remains a great challenge. Herein, we report the spontaneous phase transformation of MoS2 from the 2H to the 1T phase, caused by the strong metal–support interaction during iridium (Ir) adsorption. The resulting Ir/MoS2 heterostructures show higher catalytic activity for overall water splitting than those of commercial Pt/C and IrO2 in alkaline media. We believe that the spontaneous phase transformation of this material not only opens up a new perspective for developing advanced catalysts for alkaline water splitting but also presents an efficient and intriguing method for the phase engineering of two-dimensional materials.