Optimized Copper-Modified Zinc Oxide Photoanodes for Solar-to-Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Photocatalysis

Background:

• Developing efficient and cost-effective photoanodes is crucial for sustainable hydrogen production.
• Zinc oxide (ZnO) is a promising semiconductor material, but its photocatalytic efficiency needs enhancement.
• Copper (Cu) modification can improve the optoelectronic properties of ZnO.

Purpose of the Study:

• To present a scalable, single-step method for producing cost-efficient copper-modified zinc oxide (Cu-ZnO) photoanodes.
• To investigate the effect of copper incorporation on ZnO photoanode performance.
• To enhance the stability of the photoanodes for photoelectrochemical (PEC) applications.

Main Methods:

• Scalable chemical vapor deposition (CVD) for Cu-ZnO photoanode fabrication.
• Optimization of copper loading in ZnO films.
• Characterization using photoluminescence spectroscopy.
• Protection layer deposition via atomic layer deposition (ALD) of amorphous TiO2.
• Photoelectrochemical (PEC) cell testing.

Main Results:

• An optimized Cu-ZnO sample (CZO-5.6) achieved a stable photocurrent of 1.22 mA cm⁻² at 1.23 V_RHE with 89% Faradaic efficiency.
• Surface plasmon resonance (SPR) effects from copper nanoparticles enhanced performance.
• Amorphous TiO2 coatings provided excellent stability in alkaline solutions and efficient hole transport.

Conclusions:

• A cost-efficient method for producing high-performance Cu-ZnO photoanodes was demonstrated.
• Copper modification and TiO2 protection significantly improve photocatalytic activity and stability.
• This approach offers a low-cost route for developing efficient photocatalysts for hydrogen production.