Synthesis of a highly durable and efficient Ir-functionalized OAPS-GMA dendrimer for an all-pH hydrogen evolution reaction

Abstract

The hydrogen evolution reaction (HER) is a critical challenge to achieve energy-efficient water electrolysis for the production of hydrogen and other solar fuels. Herein, we report the synthesis of an efficient Ir-functionalized silsesquioxane-glycidyl methacrylate dendrimer (Ir-OAPS-GMA) via the hydrothermal method, utilizing an organic–inorganic hybrid OAPS-GMA dendrimer for the first time. The unique combination of crystalline Ir and amorphous OAPS-GMA phases in a single structure provides abundant exposed active sites and significantly enhanced electrochemical surface area. The Ir-OAPS-GMA catalyst demonstrates outstanding performance in the electrocatalytic HER across universal-pH with a large current density, achieving low overpotentials of 18.8, 61.4, and 85.5 mV in 1 M KOH and overpotentials of 35.8, 71.3, and 95.3 mV in 0.5 M H₂SO₄ to reach the current densities of 10, 50, and 100 mA cm⁻², respectively. Notably, Ir-OAPS-GMA exhibits remarkable long-term stability, retaining its performance for 340 h without significant degradation. Furthermore, Ir-OAPS-GMA was employed as a cathode electrode in a fabricated single-cell anion exchange membrane water electrolyzer (AEMWE) for commercial viability, requiring a low voltage of 1.58 V at 100 mA cm⁻² in 1 M KOH electrolyte. This work offers a promising pathway for designing efficient HER electrocatalysts with high active site exposure, advancing sustainable hydrogen production technology.