An amorphous MoS modified g-C₃N₄ composite for efficient photocatalytic hydrogen evolution under visible light

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Graphitic carbon nitride (g-C₃N₄) is a promising metal-free semiconductor photocatalyst.
• Enhancing the photocatalytic activity of g-C₃N₄ for hydrogen evolution remains a key challenge.
• Molybdenum disulfide (MoS ) has shown potential in improving photocatalytic performance.

Purpose of the Study:

• To fabricate a novel MoS /g-C₃N₄ composite photocatalyst.
• To investigate the hydrogen-evolution performance of the composite under visible light.
• To understand the mechanism behind the enhanced photocatalytic activity.

Main Methods:

• Sonochemical synthesis of MoS /g-C₃N₄ composite.
• Hydrothermal method for amorphous MoS synthesis.
• Two-step thermal polycondensation for g-C₃N₄ nanosheet production.
• Visible light photocatalytic hydrogen evolution testing.

Main Results:

• The MoS /g-C₃N₄ (7 wt%) composite exhibited a maximum H₂-evolution rate of 1586 μmol g^-1 h^-1.
• This rate is approximately 70 times higher than that of pure g-C₃N₄ nanosheets.
• The composite demonstrated enhanced photoinduced electron-hole pair separation and provided numerous active sites.

Conclusions:

• The fabricated MoS /g-C₃N₄ composite significantly enhances visible-light-driven hydrogen evolution.
• The improved performance is attributed to the formation of intimate heterojunctions and efficient charge separation.
• MoS acts as an effective co-catalyst, boosting the H⁺ to H₂ conversion efficiency.