Stepped-Current-Controlled Evolution of Cu(OH)₂/CuO Tandem Nanostructure for Efficient Photothermal Conversion

Area of Science:

• Materials Science
• Energy Conversion
• Nanotechnology

Background:

• Photothermal conversion efficiently converts sunlight to thermal energy, crucial for energy systems.
• Copper is a good heat conductor but has poor solar absorption, limiting its use in photothermal applications.
• Existing copper oxide coatings often lack sufficient solar spectrum absorption.

Purpose of the Study:

• To develop efficient photothermal coatings using copper oxides on copper surfaces.
• To investigate the structural evolution and optical properties of electrochemically synthesized copper oxides.
• To evaluate the performance of these coatings in solar-driven heating and de-icing.

Main Methods:

• Electrochemical anodization of copper surfaces to create vertically aligned copper oxides.
• Characterization of the resulting nanostructures (Cu(OH)2 nanowires and CuO nanosheets).
• Measurement of solar absorption spectra and photothermal conversion efficiency under solar illumination.

Main Results:

• Successfully synthesized CuO nanosheets with strong light absorption from 200-1200 nm.
• Achieved a water temperature of 102.6°C within 20 minutes using CuO-coated copper tubes under one sun illumination.
• Demonstrated a 73.6% photothermal conversion efficiency, more than double that of pristine copper, and rapid de-icing in 700 seconds.

Conclusions:

• Vertically aligned CuO nanosheets synthesized via electrochemical anodization significantly enhance photothermal conversion efficiency.
• These enhanced photothermal coatings show great promise for applications like solar water heating, seawater desalination, and energy generation.