Stabilization and Regeneration of CeO2 and CeO2/ZrO2 based Pt catalyst for the water gas shift reaction

The article deals with stabilisation and regeneration of CeO2 and CeO2/ZrO2 based Pt water gas shift catalysts, subject to high initial deactivation. The reaction gas species effect on the catalyst deactivation was investigated by H2-TPR. Activity measurements enabled the effect of different promoters, some added to the CeO2 based catalysts and some to the CeO2/ZrO2 based Pt catalysts, to be investigated. The catalysts were also characterised by BET and CO-TPR. Deactivated catalysts activity was restored by using various regeneration methods. Of the two selected carriers the CeO2/ZrO2 based Pt catalyst showed the highest resilience to deactivation. For the two different carriers, CeO2 and CeO2/ZrO2, W and Re were the best promoters when the catalyst was subject to deactivation. Experiments with H2-TPR indicate a fast initial change in the platinum oxides concentration and composition. The CO-TPR was used to make conclusions about the various regeneration effects of water and oxygen on the catalyst. Finally it is suggested that not one deactivation mechanism is possible and which mechanism that dominates is dependant on the catalyst and the reaction gas composition.