Nature Communications 5: Article number: 5723 (2014); Published: 4 December 2014; Updated: 5 February 2015 The financial support for this Article was not fully acknowledged. The Acknowledgements should have read: This work was supported as part of the Methane Opportunities for Vehicular Energy (MOVE) Program under the Award Number DE-AR0000249 and as part of the Center for Gas Separations Relevant to Clean Energy Technologies, an Energy Frontier Research Center (EFRC) funded by the U.