Dealloying-Derived Self-Supporting Nanoporous Zinc Film with Optimized Macro/Microstructure for High-Performance...

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Solar steam generation (SSG) is crucial for freshwater production, addressing global water scarcity.
• Nanostructured metals show promise for SSG due to localized surface plasmon resonance, but low-cost, high-performance films are needed.

Purpose of the Study:

• To develop a cost-effective method for fabricating high-performance nanoporous metal films for SSG.
• To investigate the dealloying mechanism and structural evolution of zinc-based alloys for optimized solar absorbers.

Main Methods:

• A one-step dealloying process was used to create self-supporting black nanoporous zinc (NP-Zn) films from Al-Zn alloys.
• Alloy composition effects on NP-Zn formation and microstructure were studied, with Al98Zn2 selected as optimal.
• In situ and ex situ characterizations detailed the dealloying mechanism, phase transitions, and porosity development.

Main Results:

• The optimal Al98Zn2 alloy yielded NP-Zn films with a bicontinuous ligament/channel structure, high porosity (81.3%), and significant volume shrinkage (89.8%).
• These NP-Zn films exhibited broadband absorption and superior hydrophilicity.
• The NP-Zn2 film demonstrated high evaporation efficiency, excellent stability, and effective seawater desalination capabilities.

Conclusions:

• The developed NP-Zn films offer a low-cost, efficient, and stable solution for solar steam generation.
• The material's properties make it a promising candidate for metal-based photothermal materials in solar water purification applications.