1. Laboratory of Forest Products Chemistry, Helsinki University of Technology, P.O. Box 6300, FIN-02015 TKK, Finland, Laboratory of Physical Chemistry and Electrochemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 TKK, Finland, and Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands