1. Center for Hydrogen Energy Technologies, Lithuanian Energy Institute, 3 Breslaujos, 44403 Kaunas, Lithuania
2. Institute of Solid State Physics, University of Latvia, LV-1063 Riga, Latvia
3. Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland, 102 Reykjavik, Iceland
4. IceTec, 112 Reykjavik, Iceland