Phase‐Dependent Reverse Electronic Metal‐Support Interaction to Boost Alkaline Hydrogen Evolution

Abstract Electronic metal‐support interaction (EMSI) represents a pivotal strategy for modulating the electronic structure of supported metals and enhancing their catalytic performance. However, limited reports have been conducted on the impact of the support crystal phase on EMSI. Here, a charge transfer inversion phenomenon associated with support crystal phase regulation is systematically revealed. Specifically, subnano‐sized noble metals (e.g., Pt, Rh, Ru) donate electrons to 2H‐MoS 2 support, whereas a reverse electron transfer direction is observed when these noble metals are supported on 1T‐MoS 2 . Electron‐enriched noble metals demonstrate significantly higher activity for alkaline hydrogen evolution compared to their electron‐deficient counterparts, with 1T‐MoS 2 @Pt achieving an exceptionally low overpotential of 18 mV at 10 mA cm −2 . Furthermore, an anion exchange membrane water electrolyzer (AEMWE) incorporating 1T‐MoS 2 @Pt as the cathode exhibits superior catalytic activity and sustained stability at ampere‐level current density. This work provides novel insights into developing efficient catalysts by regulating charge transfer dependent on the support crystal phase.