Phosphated IrMo bimetallic cluster for efficient hydrogen evolution reaction

Developing low-cost, high-performance electrocatalysts for the hydrogen evolution reaction (HER) is essential for producing hydrogen from renewable energy sources. Herein, we report phosphated IrMo bimetallic clusters supported by macroporous nitrogen-doped carbon (IrMoP/MNC) as a highly efficient alkaline HER catalyst. The experimental and theoretical results demonstrate that P and Mo synergistically tune the electronic structure of atomically dispersed Ir to improve adsorption of the reactant H₂O and desorption of the product OH⁻. P itself serves as an active site and cooperates with the nearby Ir atom to significantly enhance the HER kinetics. Even with only 2.6 ​wt% Ir in the catalyst, IrMoP/MNC exhibits an ultralow overpotential of 14 ​mV at 10 ​mA ​cm⁻², as well as an unprecedented high mass activity of 18.58 A mg_Ir⁻¹ at an overpotential of 100 ​mV, superior to commercial Pt/C and overwhelmingly better than other Ir-based electrocatalysts. This study demonstrates a multi-level design strategy to effectively improve the atom efficiency of a noble metal, involving spatial geometry, local electronic structure, and dual-atom synergy.