Nearly 100% selective and visible-light-driven methane conversion to formaldehyde via. single-atom Cu and W<sup>δ</sup>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37165020.
- Also identified by DOI 10.1038/s41467-023-38334-7 and PMC identifier 10172301.
- 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
Direct solar-driven methane (CH<sub>4</sub>) reforming is highly desirable but challenging, particularly to achieve a value-added product with high selectivity. Here, we identify a synergistic ensemble effect of atomically dispersed copper (Cu) species and partially reduced tungsten (W<sup>δ+</sup>), stabilised over an oxygen-vacancy-rich WO<sub>3</sub>, which enables exceptional photocatalytic CH<sub>4</sub> conversion to formaldehyde (HCHO) under visible light, leading to nearly 100% selectivity, a very high yield of 4979.0 μmol·g<sup>-1</sup> within 2 h, and the normalised mass activity of 8.5 × 10<sup>6</sup> μmol·g<sup>-1</sup><sub>Cu</sub>·h<sup>-1</sup> of HCHO at ambient temperature. In-situ EPR and XPS analyses indicate that the Cu species serve as the electron acceptor, promoting the photo-induced electron transfer from the conduction band to O<sub>2</sub>, generating reactive •OOH radicals. In parallel, the adjacent W<sup>δ+</sup> species act as the hole acceptor and the preferred adsorption and activation site of H<sub>2</sub>O to produce hydroxyl radicals (•OH), and thus activate CH<sub>4</sub> to methyl radicals (•CH<sub>3</sub>). The synergy of the adjacent dual active sites boosts the overall efficiency and selectivity of the conversion process.