Preparation of mesoporous Cu/Zn/Ce/Zr/Al catalysts and activity in steam reforming of methanol

Ammonium carbonate-assisted mechanochemical preparation of Cu-based catalysts has been developed for steam reforming of methanol (SRM). The characteristics of the catalysts were studied by N2 adsorption–desorption, N2O titration, TEM, XRD, XPS, H2-TPR, and TG analysis. Optimized-prepared samples showed a porous structure with high surface areas due to the ammonium carbonate decomposing during the calcination. Because of the positive correlation between surface area and catalytic activity, the porous catalysts exhibited superior SRM activity, e.g., Cu1Zn1Zr1Al7 with a high surface area of 147.1 m2 g−1 reached a maximum methanol conversion of 85.2%. Furthermore, more Cu–Al spinels were introduced on Cu1Zn1Al8 by the milling process compared to wet-impregnated IM-Cu1Zn1Al8. Ascribed to the interaction of dispersed copper components with the surface oxygen vacancies of the CeO2/ZrO2, the promoted reducibility was observed with reduction peaks observed at low temperatures of 170 and 152 °C. With CexZr1−xO2 solid solution in Cu1Zn1Ce1Zr1Al6, a high surface-oxygen population was clearly formed on the surface, which suppressed CO production (0.8%) in the reaction. The ball-milled catalysts were found to have a much better catalytic time-on-stream stability, while the degradation of IM-Cu1Zn1Al8 was mainly ascribed to Cu sintering in the reaction, not the carbon deposits.