II.a Catalyst preparation 13 mmol of Ni(NO3)2•6H2O, 26 mmol of Fe(NO3)3•9H2O and 13 or 38 mmol of glycine, respectively were dissolved in 100 mL of deionised water, stirred for 30 minutes and heated to evaporate the water and to form a gel, which ignited upon further heating leaving a foamy material. The product was ground in a mortar and used for experiments as prepared. An additional batch was prepared for O2-and CO2-TPDs.