Halide doping and morphology engineering in bismuth-based MOFs for enhanced water oxygen evolution

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Precise morphology control in metal-organic frameworks (MOFs) is essential for optimizing photocatalytic performance.
• Bismuth-based MOFs show promise for solar water splitting applications.

Purpose of the Study:

• To develop a scalable, template-free method for engineering the morphology of bromine-doped bismuth terephthalate (BiBDC) MOFs.
• To investigate the structure-property relationships between MOF morphology and photocatalytic activity in solar water splitting.

Main Methods:

• A one-pot solvothermal strategy was employed to synthesize BiBDC MOFs with varying Br:Bi molar ratios.
• Morphological characterization was performed to analyze the evolution of structures from rod-like to mace-like and flower-like.
• Photocatalytic oxygen evolution rates were measured under visible light irradiation.

Main Results:

• Tuning the Br:Bi molar ratio resulted in distinct BiBDC morphologies, including rod-like, mace-like, and flower-like structures.
• The mace-like BiBDC-0.5 exhibited superior surface area, preferential crystal orientation, and more active sites compared to other morphologies.
• This optimized morphology led to a high visible light oxygen evolution rate of 15.2 μmol h⁻¹, with excellent stability over 10 hours.

Conclusions:

• Halide doping and morphology engineering are effective strategies for enhancing the performance of bismuth-based MOFs.
• The developed method provides a scalable and template-free route for fabricating high-performance photocatalysts for solar-driven water oxygen evolution.