Photochargeable Mn-Based Metal-Organic Framework and Decoupled Photocatalysis

Area of Science:

• Materials Science
• Energy Conversion
• Photocatalysis

Background:

• Mimicking natural photosynthesis's light-dark decoupling is crucial for advanced energy conversion materials.
• Developing precious metal-free materials is essential for sustainable energy solutions.

Purpose of the Study:

• To design and synthesize a novel metal-organic framework (MOF) for efficient photocharging and subsequent dark reactions.
• To investigate the material's performance in emulating the light-decoupled reactivity of photosynthesis.

Main Methods:

• Synthesis of a precious metal-free MOF (MnBr-253) using Al nodes, bipyridine linkers, and MnBr(CO)3(bipyridine) complexes.
• Photoirradiation experiments to measure electron photocharging capacity and rate.
• Spectroscopic and computational analyses to understand electron accumulation mechanisms.
• Application of charged MOF for hydrogen evolution under dark conditions.

Main Results:

• MnBr-253 exhibited a high electron photocharging capacity (~42 C·g⁻¹ MOF) and a state-of-the-art photocharging rate (1.28 C·s⁻¹·g⁻¹ MOF).
• Achieved an incident photon-to-electron conversion efficiency of ~9.4% at 450 nm.
• Demonstrated successful application of charged MnBr-253 for dark hydrogen evolution, mimicking photosynthesis.

Conclusions:

• The synthesized MnBr-253 MOF effectively stores light energy for subsequent dark reactions.
• High porosity and manganese loading contribute to the material's excellent electron storage performance.
• This MOF presents a promising pathway for artificial photosynthesis and sustainable energy conversion.