Carbonized polymer dots modified ZnIn₂S₄ microspheres for visible-light-driven hydrogen evolution promotion...

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Heterojunctions improve photocatalytic efficiency by separating light-induced electron-hole pairs.
• ZnIn2S4 (ZIS) is a semiconductor with potential for photocatalysis.
• Carbonized polymer dots (CPDs) can enhance material properties.

Purpose of the Study:

• To synthesize a carbonized polymer dots/ZnIn2S4 (CPDs/ZIS) heterostructure.
• To evaluate its enhanced photocatalytic efficiency for hydrogen production.
• To elucidate the underlying mechanism of improved performance.

Main Methods:

• Hydrothermal synthesis of CPDs/ZIS heterostructure.
• Photocatalytic hydrogen evolution rate measurements under visible light.
• Density Functional Theory (DFT) calculations and Gibbs free energy analysis.

Main Results:

• The CPDs/ZIS composite exhibited a hydrogen evolution rate of 133 μmol g⁻¹ h⁻¹, 8.9 times higher than pure ZIS.
• CPDs enhanced light absorption, charge carrier lifetime, and specific surface area.
• DFT and Gibbs free energy calculations indicated decreased H* adsorption free energy and introduced transition states.

Conclusions:

• The synthesized CPDs/ZIS heterostructure demonstrates superior photocatalytic activity for hydrogen evolution.
• CPDs effectively promote charge separation and transmission, accelerating the reaction.
• A direct Z-type heterojunction mechanism is proposed for the enhanced hydrogen evolution activity.