High Catalytic Selectivity of Electron/Proton Dual‐Conductive Sulfonated Polyaniline Micropore Encased IrO2 Electrocatalyst by Screening Effect for Oxygen …

Abstract

Acidic seawater electrolysis offers significant advantages in high efficiency and sustainable hydrogen production. However, in situ electrolysis of acidic seawater remains a challenge. Herein, a stable and efficient catalyst (SPTTPAB/IrO₂) is developed by coating iridium oxide (IrO₂) with a microporous conjugated organic framework functionalized with sulfonate groups (-SO₃H) to tackle these challenges. The SPTTPAB/IrO₂ presents a -SO₃H concentration of 5.62 × 10^-4 mol g^-1 and micropore below 2 nm numbering 1.026 × 10¹⁶ g^-1. Molecular dynamics simulations demonstrate that the conjugated organic framework blocked 98.62% of Cl^- in seawater from reaching the catalyst. This structure combines electron conductivity from the organic framework and proton conductivity from -SO₃H, weakens the Cl^- adsorption, and suppresses metal-chlorine coupling, thus enhancing the catalytic activity and selectivity. As a result, the overpotential for the oxygen evolution reaction (OER) is only 283 mV@10 mA cm^-2, with a Tafel slope of 16.33 mV dec^-1, which reduces 13.8% and 37.8% compared to commercial IrO₂, respectively. Impressively, SPTTPAB/IrO₂ exhibits outstanding seawater electrolysis performance, with a 35.3% improvement over IrO₂ to 69 mA cm^-2@1.9 V, while the degradation rate (0.018 mA h^-1) is only 24.6% of IrO₂. This study offers an innovative solution for designing high-performance seawater electrolysis electrocatalysts.