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The development of the proton exchange membrane water electrolyzer (PEMWE) is still limited by the prohibitive cost and scarcity of iridium (Ir)‐based oxygen evolution reaction (OER) catalyst. This work presents a novel catalyst synthesized by precursor‐atomization and rapid joule‐heating method, successfully doping iridium atoms into polyvalent tungsten blends (W0, W5+, W6+) based on titanium substrate. The vacancy engineering of unsaturated tungsten oxide (W5+, W6+) reconstructs the electronic structure of the catalyst surface, which resulting in the low‐valence state iridium species, avoiding excessive oxidation of iridium and accelerating the catalytic kinetics. Meanwhile, metallic tungsten (W0) improves the conductivity of catalyst and guarantees the stable existence of oxygen vacancy. The TiIrWOx possesses excellent performance in acidic OER catalysis, requiring overpotential of only 181 mV to drive 10.0 mA cm−2, and exhibiting a high mass activity of 753 A gIr−1 at an overpotential of 300 mV. The membrane electrode assembly (MEA) with TiIrWOx as anode electrocatalyst can reduce the Ir consumption amount by >60% compared to commercial IrO2, and it can operated over 120 h at a current density of 1.0 A cm−2. [ABSTRACT FROM AUTHOR]

Seawater electrolysis is an attractive technique for massive green hydrogen production owing to the dominant advantages of seawater resources, namely low‐cost and limitlessness. However, the oxygen evolution reaction (OER) catalysts will be easily deactivated for severe seawater Cl− permeation and corrosion. Herein, a structural buffer engineering strategy is reported to endow the Co2(OH)3Cl with long‐term operation stability and a high OER selectivity of ≈99.6% in seawater splitting. The lattice Cl− of Co2(OH)3Cl can act as the structural buffer, whose continuous leaching during OER can leave vacancies for seawater Cl− invasion, so as to avoid catalyst deactivation. Accordingly, Co2(OH)3Cl can maintain 99.9% of its initial current density after 60 000 s operation, while that of Co(OH)2 decays by 52.7% in 7 000 s. Meanwhile, the lattice Cl− of Co2(OH)3Cl can optimize the binding energy of reaction intermediates on the neighboring OCoO site. Thus, Co2(OH)3Cl exhibits a current density of 330.5 mA cm–2 at the potential of 1.63 V versus RHE, 45.9 times higher than that of Co(OH)2. The structural buffer strategy may be applied to incorporate other metal oxides with suitable anions, and effectively boost their OER activity and stability in alkaline seawater. [ABSTRACT FROM AUTHOR]

Producing hydrogen via water electrolysis could be a favorable technique for energy conversion, but the freshwater shortage would inevitably limit the industrial application of the electrolyzers. Being an inexhaustible resource of water on our planet, seawater can be a promising alternative electrolyte for industrial hydrogen production. However, many challenges are hindering the actual application of seawater splitting, especially the competing reactions relating to chlorine at the anode that could severely corrode the catalysts. The execution of direct seawater electrolysis needs efficient and robust electrocatalysts that can prevent the interference of competing reactions and resist different impurities. In recent years, researchers have made great advances in developing high-efficiency electrocatalysts with improved activity and stability. This review will provide the macroscopic understanding of direct seawater splitting, the strategies for rational electrocatalyst design, and the development prospects of hydrogen production via seawater splitting. The nonprecious metal-based electrocatalysts for stable seawater splitting and their catalytic mechanisms are emphasized to offer guidance for designing the efficient and robust electrocatalyst, so as to promote the production of green hydrogen via seawater splitting. [ABSTRACT FROM AUTHOR]