Lithium carbonate-promoted mixed rare earth oxides as a generalized strategy for oxidative coupling of methane with exceptional yields.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38012194.
- Also identified by DOI 10.1038/s41467-023-43682-5 and PMC identifier 10682025.
- 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 oxidative coupling of methane to higher hydrocarbons offers a promising autothermal approach for direct methane conversion, but its progress has been hindered by yield limitations, high temperature requirements, and performance penalties at practical methane partial pressures (~1 atm). In this study, we report a class of Li<sub>2</sub>CO<sub>3</sub>-coated mixed rare earth oxides as highly effective redox catalysts for oxidative coupling of methane under a chemical looping scheme. This catalyst achieves a single-pass C<sub>2+</sub> yield up to 30.6%, demonstrating stable performance at 700 °C and methane partial pressures up to 1.4 atm. In-situ characterizations and quantum chemistry calculations provide insights into the distinct roles of the mixed oxide core and Li<sub>2</sub>CO<sub>3</sub> shell, as well as the interplay between the Pr oxidation state and active peroxide formation upon Li<sub>2</sub>CO<sub>3</sub> coating. Furthermore, we establish a generalized correlation between Pr<sup>4+</sup> content in the mixed lanthanide oxide and hydrocarbons yield, offering a valuable optimization strategy for this class of oxidative coupling of methane redox catalysts.