Accelerate charge separation in Cu₂O/MoO₂ photocathode for photoelectrocatalytic hydrogen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Photoelectrocatalyzing water reduction is crucial for sustainable energy.
• Copper(I) oxide (Cu₂O) is a promising photocathode material but suffers from charge recombination and photocorrosion.
• Developing stable and efficient photocathodes is essential for practical applications.

Purpose of the Study:

• To prepare and investigate a novel Cu₂O/MoO₂ composite photocathode.
• To understand the role of molybdenum dioxide (MoO₂) in enhancing the performance of Cu₂O.
• To improve the photocurrent density, energy conversion efficiency, and stability of photocathodes for water reduction.

Main Methods:

• In situ electrodeposition of MoO₂ onto Cu₂O.
• Systematic theoretical and experimental studies.
• Photoelectrochemical characterization.

Main Results:

• The Cu₂O/MoO₂ photocathode demonstrated significantly enhanced photocurrent density and energy conversion efficiency.
• MoO₂ effectively passivated surface states and accelerated reaction kinetics of Cu₂O.
• MoO₂ promoted directional migration and separation of photogenerated charges.
• An internal electric field formed by MoO₂ inhibited Cu⁺ reduction, enhancing photoelectrochemical stability.

Conclusions:

• The developed Cu₂O/MoO₂ photocathode exhibits high activity and stability for water reduction.
• MoO₂ acts as an effective co-catalyst and charge separator, overcoming limitations of pure Cu₂O.
• This work provides a pathway for designing advanced photocathodes for sustainable energy applications.