Elucidating protonation pathways in CO<sub>2</sub> photoreduction using the kinetic isotope effect.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38200030.
- Also identified by DOI 10.1038/s41467-024-44753-x and PMC identifier 10781958.
- 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 surge in anthropogenic CO<sub>2</sub> emissions from fossil fuel dependence demands innovative solutions, such as artificial photosynthesis, to convert CO<sub>2</sub> into value-added products. Unraveling the CO<sub>2</sub> photoreduction mechanism at the molecular level is vital for developing high-performance photocatalysts. Here we show kinetic isotope effect evidence for the contested protonation pathway for CO<sub>2</sub> photoreduction on TiO<sub>2</sub> nanoparticles, which challenges the long-held assumption of electron-initiated activation. Employing isotopically labeled H<sub>2</sub>O/D<sub>2</sub>O and in-situ diffuse reflectance infrared Fourier transform spectroscopy, we observe H<sup>+</sup>/D<sup>+</sup>-protonated intermediates on TiO<sub>2</sub> nanoparticles and capture their inverse decay kinetic isotope effect. Our findings significantly broaden our understanding of the CO<sub>2</sub> uptake mechanism in semiconductor photocatalysts.