Stable and efficient methane production. (IMAGE) City University of Hong Kong Caption In contrast to the bare cuprous oxide sample, which lost its intrinsic activity in the fifth run, cuprous oxide with MOF shell retained 69.2% of its original efficiency for methane production after five runs. Credit DOI number: 10.1002/anie.202015735 Usage Restrictions Image must be used with appropriate caption and credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.