Effects of catalyst preparation route and promoters (Ce and Zr) on catalytic activity of CuZn/CNTs catalysts for hydrogen production from methanol steam reforming

Ce or Zr promoted CuZn/CNTs (carbon nanotubes) catalysts were synthesized by microwave-assisted polyol, co-precipitation and impregnation methods and were used to generate hydrogen by methanol steam reforming (MSR) process. The physico-chemical properties of the prepared catalysts were analyzed by BET, XRD, FT-IR, TEM, FE-SEM, EDX-dot mapping and H₂-TPR methods. The effect of various operating parameters on methanol conversion and selectivity of gaseous products was investigated. The results indicated that the addition of 2 wt% CeO₂ promoter on CuZn/CNTs catalyst synthesized by impregnation route (CuZn/CNTs (Imp)) increased its methanol conversion from 81.3 to 85.2%, and decreased its CO selectivity from 6.2 to 3.8% at 300 °C, WHSV of 7.5 h^?1 and S/C molar ratio of 2. In addition, the CeCuZn/CNTs catalyst prepared via the microwave-assisted polyol route (CeCuZn/CNTs (Pol)) exhibited the best catalytic activity with 98.2% hydrogen selectivity, 2.6% CO selectivity and 94.2% methanol conversion at 300 °C. Furthermore, a 48 h continuous MSR reaction at 300 °C, identified CeCuZn/CNTs (Pol) as the most stable catalyst due to its higher metal particle dispersion and better interaction between the active phase and the CNTs support.