Effect of Fe/Cu ratio on the activity of Fe-Al-Cu catalysts for water gas shift reaction under hydrogen-rich atmosphere

摘要

Catalysts with different Fe/Cu molar ratios were prepared by co-precipitation method and evaluated under hydrogen-rich atmosphere (H_2 = 72.2 vol%). The effect of Fe/Cu ratio on the activity of Fe-Al-Cu catalysts for water gas shift reaction (WGSR) was investigated. The samples were characterized by X-ray diffraction (XRD), Temperature programmed reduction (TPR) and Brunauer-Emmett-Teller (BET) techniques. The results suggested that the optimal Fe/Cu ratio of Fe-Al-Cu catalyst was 1:1 and its highest CO conversion efficiency is 97.8% at 300 ℃, excessive Cu resulted in poor catalytic activity. Fe-Al-Cu catalysts possessed a good activity at 250-550 ℃ and their CO conversions reached 87.3% and 84.6% at 250 ℃ and 550 ℃, respectively, which is ascribed to the fact that copper not only acts as an active role for water gas shift reaction at 250 ℃ but also conducts as an electronic promoter in solid solution at higher temperature. Furthermore, magnetite had catalytic effect at higher temperature.