Self-Assembled 8-Ti-Containing Polyoxomolybdate for the Photocatalytic Hydrogen Evolution

Area of Science:

• Inorganic Chemistry
• Materials Science
• Catalysis

Background:

• Polyoxomolybdates are versatile inorganic clusters with diverse structures and applications.
• The development of novel polyoxomolybdate structures with enhanced catalytic properties is an active area of research.
• Lacunary Keggin-type structures offer unique opportunities for designing functional materials.

Purpose of the Study:

• To synthesize and characterize a novel S-shaped polyoxomolybdate containing eight titanium centers.
• To investigate the structural novelty of the {GeMo5O23} fragment and its contribution to the polyoxomolybdate family.
• To evaluate the photocatalytic performance of the synthesized compound for hydrogen evolution.

Main Methods:

• One-pot hydrothermal synthesis method.
• Single-crystal X-ray diffraction for structural determination.
• Photocatalytic hydrogen evolution studies under optimized conditions.

Main Results:

• Synthesis of an S-shaped 8-Ti-containing polyoxomolybdate, (NH4)Cs2Na6H3[Ti8(GeMo9O34)2(GeMo5O23)2]·44H2O.
• Discovery of a rare {GeMo5O23} fragment, enriching the lacunary Keggin-type family.
• The compound exhibits the highest nuclearity of Ti centers among reported polyoxomolybdates.
• Achieved a hydrogen evolution rate of 2392.6 μmol g⁻¹ h⁻¹ using the compound as a heterogeneous catalyst.

Conclusions:

• The successful synthesis and characterization of a novel, highly nuclear titanium-containing polyoxomolybdate.
• The discovery of a new {GeMo5O23} fragment expands the structural diversity of polyoxomolybdates.
• The synthesized compound shows significant potential as an efficient heterogeneous catalyst for photocatalytic hydrogen production.