The influence of La-doping on the activity and stability of Cu/ZnO catalyst for the low-temperature water–gas shift reaction

The influence of lanthanum (La) doping on the performance of 37 wt% Cu/ZnO catalysts for the low-temperature water–gas shift (LT-WGS) reaction was investigated. A 2.3 wt% La loading improved catalyst activity compared to the neat Cu/ZnO and Cu/ZnO/Al2O3 systems and was accompanied by a lowering of the activation energy. Higher La loadings promoted the adsorption of H2O at the expense of CO, resulting in a decrease in LT-WGS activity. Additionally, 2.3 wt% La acted to stabilise catalyst activity compared with the neat Cu/ZnO. XPS and H2-TPR assessment demonstrated a strong interaction between Cu and La components, while data from CO and H2O-TPD studies favoured the associative WGS mechanism in this instance. Activity and stability findings also suggested metallic Cu was not responsible for LT-WGS activity.