Hydrogen Production from the Decomposition of Hydrogen Iodide over Nanosized Nickel-Oxide-zirconia Catalysts Prepared by Solution-Combustion Techniques

NiO/ZrO2 prepared by solution-combustion method (SCM) showed near equilibrium conversions of hydrogen iodide to hydrogen and iodine at 500°C–550°C without any performance degradation over 50h. XRD data of the catalyst after 10h of reaction were compared with the same after a TPR step in H2/Ar on another catalyst sample, to verify Ni-ex-solution. Ni is clearly visible in the XRD after TPR, although it was not observed under reaction conditions (HI/H2O/N2), even after 10h. Instead, the onset of monoclinic ZrO2 is observed after reaction, which was not visible after TPR.