1. Division of Nanotechnology and Functional Materials, Department of Materials Science and Engineering, The Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, Uppsala 751 03, Sweden
2. Center for Green Chemistry and Green Engineering, School of the Environment, Yale University, 195 Prospect Street, New Haven, Connecticut 06511, United States
3. Department of Earth Sciences, Uppsala University, P.O. Box 256, Uppsala 751 05, Sweden