1. Institute
of Materials and Environmental Chemistry, Research Centre for Natural
Sciences, Hungarian Academy of Sciences, P.O. Box 286, Budapest, 1519 Hungary
2. SINTEF Energy Research, Postboks 4761 Sluppen, NO-7465 Trondheim, Norway
3. Department
of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway