Multifunctional Design of Catalysts for Seawater Electrolysis for Hydrogen Production

Direct seawater electrolysis is a promising technology within the carbon-neutral energy framework, leveraging renewable resources such as solar, tidal, and wind energy to generate hydrogen and oxygen without competing with the demand for pure water. High-selectivity, high-efficiency, and corrosion-resistant multifunctional electrocatalysts are essential for practical applications, yet producing stable and efficient catalysts under harsh conditions remains a significant challenge. This review systematically summarizes recent advancements in advanced electrocatalysts for seawater splitting, focusing on their multifunctional designs for selectivity and chlorine corrosion resistance. We analyze the fundamental principles and mechanisms of seawater electrocatalytic reactions, discuss the challenges, and provide a detailed overview of the progress in nanostructures, alloys, multi-metallic systems, atomic dispersion, interface engineering, and functional modifications. Continuous research and innovation aim to develop efficient, eco-friendly seawater electrolysis systems, promoting hydrogen energy application, addressing efficiency and stability challenges, reducing costs, and achieving commercial viability.

Recent Advances on Hydrogen Evolution and Oxygen Evolution Catalysts for Direct Seawater Splitting

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.

Oxygen Vacancies and Interface Engineering on Amorphous/Crystalline CrOx -Ni3 N Heterostructures toward High-Durability and Kinetically Accelerated Water Splitting

Manipulating catalytic active sites and reaction kinetics in alkaline media is crucial for rationally designing mighty water-splitting electrocatalysts with high efficiency. Herein, the coupling between oxygen vacancies and interface engineering is highlighted to fabricate a novel amorphous/crystalline CrO_x -Ni₃ N heterostructure grown on Ni foam for accelerating the alkaline hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory (DFT) calculations reveal that the electron transfer from amorphous CrO_x to Ni₃ N at the interfaces, and the optimized Gibbs free energies of H₂ O dissociation (ΔG_H-OH ) and H adsorption (ΔG_H ) in the amorphous/crystalline CrO_x -Ni₃ N heterostructure are conducive to the superior and stable HER activity. Experimental data confirm that numerous oxygen vacancies and amorphous/crystalline interfaces in the CrO_x -Ni₃ N catalysts are favorable for abundant accessible active sites and enhanced intrinsic activity, resulting in excellent catalytic performances for HER and OER. Additionally, the in situ reconstruction of CrO_x -Ni₃ N into highly active Ni₃ N/Ni(OH)₂ is responsible for the optimized OER performance in a long-term stability test. Eventually, an alkaline electrolyzer using CrO_x -Ni₃ N as both cathode and anode has a low cell voltage of 1.53 V at 10 mA cm^-2 , together with extraordinary durability for 500 h, revealing its potential in industrial applications.

A Facile Design of Solution-Phase Based VS2 Multifunctional Electrode for Green Energy Harvesting and Storage

This work reports the fabrication of vanadium sulfide (VS₂) microflower via one-step solvo-/hydro-thermal process. The impact of ethylene glycol on the VS₂ morphology and crystal structure as well as the ensuing influences on electrocatalytic hydrogen evolution reaction (HER) and supercapacitor performance are explored and compared with those of the VS₂ obtained from the standard pure-aqueous and pure-ethylene glycol solvents. The optimized VS₂ obtained from the ethylene glycol and water mixed solvents exhibits a highly ordered unique assembly of petals resulting a highly open microflower structure. The electrode based on the optimized VS₂ and exhibits a promising HER electrocatalysis in 0.5 M H₂SO₄ and 1 M KOH electrolytes, attaining a low overpotential of 161 and 197 mV, respectively, at 10 mA.cm^-2 with a small Tafel slope 83 and 139 mVdec^-1. In addition, the optimized VS₂ based electrode exhibits an excellent electrochemical durability over 13 h. Furthermore, the superior VS₂ electrode based symmetric supercapacitor delivers a specific capacitance of 139 Fg^-1 at a discharging current density of 0.7 Ag^-1 and exhibits an enhanced energy density of 15.63 Whkg^-1 at a power density 0.304 kWkg^-1. Notably, the device exhibits the capacity retention of 86.8% after 7000 charge/discharge cycles, demonstrating a high stability of the VS₂ electrode.

ZIF-67 derived hierarchical hollow Co3S4@Mo2S3 dodecahedron with an S-scheme surface heterostructure for efficient photocatalytic hydrogen evolution

Using ZIF-67 as a template, and the continuous temperature-raising hydrothermal method to built a heterojunction between Co3S4 and Mo2S3, this strategy synthesized a highly efficient Co3S4@Mo2S3 composite with a stable rhombohedral structure.