Photoelectrochemical water-splitting over a surface modified p-type Cr₂O₃ photocathode

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Chromium(III) oxide (Cr2O3) is a p-type semiconductor with potential for photocathodic hydrogen (H2) generation.
• Poor efficiency and stability of Cr2O3 electrodes hinder its application in photoelectrochemical (PEC) water-splitting due to high defect concentrations.

Purpose of the Study:

• To enhance the efficiency and stability of Cr2O3-based photocathodes for H2 generation.
• To investigate the effect of surface modification with TiO2 and Pt on Cr2O3 performance in PEC water-splitting.

Main Methods:

• Surface modification of Cr2O3 with n-type TiO2.
• Deposition of Platinum (Pt) nanoparticles as a co-catalyst.
• Fabrication of a multi-layered electrode for PEC water-splitting.

Main Results:

• The TiO2 overlayer passivated surface states and improved charge separation by forming a p-n junction.
• Enhanced and stabilized cathodic photocurrent was observed upon light absorption by Cr2O3.
• Demonstrated the first successful application of Cr2O3 as a light-absorbing material in a multi-layered electrode for PEC H2 generation.

Conclusions:

• TiO2/Pt modification effectively enhances the performance of Cr2O3 for PEC water-splitting.
• Cr2O3 is a viable light-absorbing material for H2 generation when properly engineered.
• This study opens new avenues for developing efficient and stable semiconductor-based photocatalysts.