1. Catalyst Development, Typpitie 1, Ecocat Oy, FI-90650 Oulu, Finland, Department of Process and Environmental Engineering, University of Oulu, Linnanmaa, FI-90014 Oulu, Finland, and National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan