1. Flemish Institute for Technological Research-VITO, Separation & Conversion Technology, Boeretang 200, Mol 2400, Belgium
2. Research and Technology Department, Vertoro B.V., Urmonderbaan 22, 6167 RD Geleen, The Netherlands
3. Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands