1. Contribution from the National Renewable Energy Laboratory (NREL), 1617 Cole Boulevard, Golden, Colorado 80401, Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, Department of Chemistry, Roskilde University (RUC), DK-4000 Roskilde, Denmark, and the Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01-224 Warsaw, Poland