Covalent organic frameworks bearing Ni active sites for free radical-mediated photoelectrochemical organic transformations.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37939175.
- Also identified by DOI 10.1126/sciadv.adi9442 and PMC identifier 10631720.
- Licence recorded as CC BY-NC.
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Abstract
Photoelectrochemical (PEC) organic transformations occurring at anodes are a promising strategy for circumventing the sluggish kinetics of the oxygen evolution reaction. Here, we report a free radical-mediated reaction instead of direct hole transfer occurring at the solid/liquid interface for PEC oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) with high selectivity. A bismuth vanadate (BiVO<sub>4</sub>) photoanode coated with a 2,2'-bipyridine-based covalent organic framework bearing single Ni sites (Ni-TpBpy) was developed to drive the transformation. Experimental studies reveal that the reaction at the Ni-TpBpy/BiVO<sub>4</sub> photoanode followed first-order reaction kinetics, boosting the formation of surface-bound ·OH radicals, which suppressed further BAD oxidation and provided a nearly 100% selectivity and a rate of 80.63 μmol hour<sup>-1</sup> for the BA-to-BAD conversion. Because alcohol-to-aldehyde conversions are involved in the valorizations of biomass and plastics, this work is expected to open distinct avenues for producing key intermediates of great value.