Three-dimensional graphene oxide cross-linked by benzidine as an efficient metal-free photocatalyst for hydrogen...

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Solar-driven water splitting for hydrogen fuel is crucial for clean energy and sustainability.
• Developing efficient, low-cost, metal-free photocatalysts is a key research objective.

Purpose of the Study:

• To synthesize and evaluate three-dimensional graphene oxide (3DG) porous materials as metal-free photocatalysts for hydrogen production via water splitting.
• To investigate the influence of cross-linkers and reduction levels on the photocatalytic activity of 3DG materials.

Main Methods:

• Preparation of 3DG porous materials by cross-linking graphene oxide (GO) sheets with aromatic diamines (benzidine, 2,2'-dimethyl-4,4'-biphenyldiamine, 4,4'-diaminodiphenylmethane) at room temperature.
• Evaluation of photocatalytic activity for hydrogen (H2) evolution under full-spectrum light.
• Tuning photoactivity by varying the mass ratio of GO to benzidine and the reduction level of 3DG.

Main Results:

• 3DG materials exhibited efficient metal-free photocatalytic activity for H2 production from water splitting.
• Benzidine-crosslinked 3DG demonstrated significantly higher H2 evolution rates compared to other cross-linkers.
• 3DG-3 (intermediate C/O ratio of 1.84) achieved the highest H2 production rate (690 μmol g-1 h-1), outperforming 2D GO and hydrothermally synthesized 3DG.
• Photocatalytic performance was linked to effective charge separation and tunable via the reduction level.

Conclusions:

• 3D graphene oxide (3DG) materials, particularly when cross-linked with benzidine, are effective metal-free photocatalysts for solar hydrogen production.
• The study demonstrates a promising pathway for developing advanced 3D materials for photocatalytic applications.
• Optimized 3DG materials offer a viable route towards sustainable hydrogen fuel generation.