Sequential co-reduction of nitrate and carbon dioxide enables selective urea electrosynthesis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38167809.
- Also identified by DOI 10.1038/s41467-023-44131-z and PMC identifier 10761727.
- 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
Despite the recent achievements in urea electrosynthesis from co-reduction of nitrogen wastes (such as NO<sub>3</sub><sup>-</sup>) and CO<sub>2</sub>, the product selectivity remains fairly mediocre due to the competing nature of the two parallel reduction reactions. Here we report a catalyst design that affords high selectivity to urea by sequentially reducing NO<sub>3</sub><sup>-</sup> and CO<sub>2</sub> at a dynamic catalytic centre, which not only alleviates the competition issue but also facilitates C-N coupling. We exemplify this strategy on a nitrogen-doped carbon catalyst, where a spontaneous switch between NO<sub>3</sub><sup>-</sup> and CO<sub>2</sub> reduction paths is enabled by reversible hydrogenation on the nitrogen functional groups. A high urea yield rate of 596.1 µg mg<sup>-1</sup> h<sup>-1</sup> with a promising Faradaic efficiency of 62% is obtained. These findings, rationalized by in situ spectroscopic techniques and theoretical calculations, are rooted in the proton-involved dynamic catalyst evolution that mitigates overwhelming reduction of reactants and thereby minimizes the formation of side products.