Ir/TiO ₂ Heterojunctions with in Situ Defects and Surface Plasmon Resonance: Chloride‐Resistant Catalyst for the Photocatalytic Hydrogen Evolution from Seawater

Photocatalytic seawater splitting for hydrogen production emerges as a promising sustainable approach to alleviate energy crises and global warming. However, its practical application is critically hindered by Cl^--induced catalyst corrosion and poor long-term stability under harsh high-salt conditions. Herein, we report a rationally designed photocatalyst comprising Ir nanoclusters uniformly dispersed on the (101) facets of a mesoporous TiO₂ matrix. This design in situ introduces Ti³⁺ species and oxygen vacancies within the TiO₂ lattice to extend light absorption. The surface plasmon resonance effect of Ir nanoclusters promotes efficient charge separation at the Ir/TiO₂ heterojunction, suppressing carrier recombination and boosting the utilization efficiency of photocarriers. Moreover, the Ir active sites demonstrate preferential coordination with H⁺/OH^- species through coordination competition, reducing the overpotential for hydrogen evolution reaction, mitigating the competitive chloride oxidation reaction, and ensuring exceptional catalytic stability. Under full-spectrum light illumination, the 1% Ir/TiO₂ catalyst achieves a hydrogen evolution rate of 0.46 mmol h^-1 (46.00 mmol g_cat ^-1 h^-1) with a remarkable turnover frequency of 1163.38 h^-1. This work establishes an effective strategy for constructing TiO₂-based photocatalysts featuring low noble metal loading, robust Cl^- corrosion resistance, and outstanding photocatalytic activity under harsh high-salt environments, offering a cost-effective route toward direct solar-driven hydrogen production from seawater.