Epitaxially grown silicon-based single-atom catalyst for visible-light-driven syngas production.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36977716.
- Also identified by DOI 10.1038/s41467-023-37401-3 and PMC identifier 10050177.
- 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
Improving the dispersion of active sites simultaneous with the efficient harvest of photons is a key priority for photocatalysis. Crystalline silicon is abundant on Earth and has a suitable bandgap. However, silicon-based photocatalysts combined with metal elements has proved challenging due to silicon's rigid crystal structure and high formation energy. Here we report a solid-state chemistry that produces crystalline silicon with well-dispersed Co atoms. Isolated Co sites in silicon are obtained through the in-situ formation of CoSi<sub>2</sub> intermediate nanodomains that function as seeds, leading to the production of Co-incorporating silicon nanocrystals at the CoSi<sub>2</sub>/Si epitaxial interface. As a result, cobalt-on-silicon single-atom catalysts achieve an external quantum efficiency of 10% for CO<sub>2</sub>-to-syngas conversion, with CO and H<sub>2</sub> yields of 4.7 mol g<sub>(Co)</sub><sup>-1</sup> and 4.4 mol g<sub>(Co)</sub><sup>-1</sup>, respectively. Moreover, the H<sub>2</sub>/CO ratio is tunable between 0.8 and 2. This photocatalyst also achieves a corresponding turnover number of 2 × 10<sup>4</sup> for visible-light-driven CO<sub>2</sub> reduction over 6 h, which is over ten times higher than previously reported single-atom photocatalysts.