Hydrogen production from steam reforming of methanol over CuO/ZnO/Al2O3 catalysts: Catalytic performance and kinetic modeling

Abstract

A series of CuO/ZnO/Al2O3, CuO/ZnO/ZrO2/Al2O3 and CuO/ZnO/CeO2/Al2O3 catalysts were prepared by coprecipitation and characterized by N2 adsorption, XRD, TPR, N2O titration and HRTEM. The catalytic performances of these catalysts for the steam reforming of methanol were evaluated in a laboratory-scale fixed-bed reactor at 0.1MPa and temperatures between 473 and 543K. The results showed that the catalytic activity depended greatly on the catalyst reducibility and the specific surface area of Cu. An approximate linear correlation between the catalytic activity and the Cu surface area was found for all catalysts investigated in this study. Compared to CuO/ZnO/Al2O3, the ZrO2-doped CuO/ZnO/Al2O3 exhibited higher activity and selectivity to CO, while the CeO2-doped catalyst displayed lower activity and selectivity. Finally, an intrinsic kinetic study was carried out over a screened CuO/ZnO/CeO2/Al2O3 catalyst in the absence of internal and external mass transfer effects. A good agreement was observed between the model-derived effluent concentrations of CO (CO2) and the experimental data. The activation energies for the reactions of methanol-steam reforming, water-gas shift and methanol decomposition over CuO/ZnO/CeO2/Al2O3 were 93.1, 85.1 and 116.5kJ·mol−1, respectively.