Water enables mild oxidation of methane to methanol on gold single-atom catalysts.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33619263.
- Also identified by DOI 10.1038/s41467-021-21482-z and PMC identifier 7900127.
- 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
As a 100% atom-economy process, direct oxidation of methane into methanol remains as a grand challenge due to the dilemma between activation of methane and over-oxidation of methanol. Here, we report that water enabled mild oxidation of methane into methanol with >99% selectivity over Au single atoms on black phosphorus (Au<sub>1</sub>/BP) nanosheets under light irradiation. The mass activity of Au<sub>1</sub>/BP nanosheets reached 113.5 μmol g<sub>catal</sub><sup>-1</sup> in water pressured with 33 bar of mixed gas (CH<sub>4</sub>:O<sub>2</sub> = 10:1) at 90 °C under light irradiation (1.2 W), while the activation energy was 43.4 kJ mol<sup>-1</sup>. Mechanistic studies revealed that water assisted the activation of O<sub>2</sub> to generate reactive hydroxyl groups and •OH radicals under light irradiation. Hydroxyl groups reacted with methane at Au single atoms to form water and CH<sub>3</sub>* species, followed by oxidation of CH<sub>3</sub>* via •OH radicals into methanol. Considering the recycling of water during the whole process, we can also regard water as a catalyst.