Photoaccumulation of Long-Lived Reactive Electrons in a Microporous Ti(IV) Oxocluster-Based Metal-Organic Framework for Light and Dark Photocatalysis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41332354.
- Also identified by DOI 10.1002/adma.202517595 and PMC identifier 12878811.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The microporous Ti<sub>12</sub> oxocluster-based metal-organic framework (MOF) MIP-177(Ti)-LT exhibits excellent stability and photoactivity, making it highly promising for photocatalysis. Using transient and photoinduced absorption spectroscopies, the behavior of reactive electrons in MIP-177(Ti)-LT across femtosecond-to-second timescales is investigated. The framework shows efficient charge separation and slow decay kinetics, with photogenerated charges persisting into the microsecond-second (µs-s) range and displaying higher yields and slower recombination than benchmark MOFs MIL-125(Ti)-NH<sub>2</sub> and UiO-66(Zr)-NH<sub>2</sub>. Photogenerated holes oxidize water with an O<sub>2</sub> yield of 335 µmol g<sup>-1</sup> h<sup>-1</sup> in the presence of electron scavengers. Under continuous irradiation, long-lived electrons accumulate, further enhanced by a hole scavenger (methanol). Remarkably, these electrons persist over 48 h post-excitation under argon, accompanied by a reversible white-to-black color change. The stored electrons remain redox-active, efficiently reducing added O<sub>2</sub> and methyl viologen. Dark addition of a Pt co-catalyst to photocharged MIP-177(Ti)-LT induces H<sub>2</sub> evolution at ≈300 µmol g<sup>-1</sup> (≈58 C g<sup>-1</sup>), corresponding to an accumulated electron density of one electron per 12 Ti atoms. These results highlight the photocharging properties of MIP-177(Ti)-LT and its potential for sustainable photocatalytic applications.