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Characterization and Activity of Cu‐MnO x /γ‐Al 2 O 3 Catalyst for Hydrogenation of Carbon Dioxide

2001; Wiley; Volume: 19; Issue: 5 Linguagem: Inglês

10.1002/cjoc.20010190502

1614-7065

Gong‐Xin Qi, Xiaoming Zheng, Jinhua Fei, Zhaoyin Hou,

Catalysis and Oxidation Reactions

Abstract The effect of manganese on the dispersion, reduction behavior and active states of surface of supported copper oxide catalysts have been investigated by XRD, temperature‐programmed reduction and XPS. The activity of methanol synthesis from CO 2 /H 2 was also investigated. The catalytic activity over CuO‐MnO x /γ‐Al 2 O 3 catalyst for CO 2 hydrogenation is higher than that of CuO/γ‐Al 2 O 3 . The adding of manganese is beneficial in enhancing the dispersion of the supported copper oxide and make the TPR peak of the CuO‐MnK x /γ‐Al 2 O 3 catalyst different from the individual supported copper and manganese oxide catalysts, which indicates that there exists strong interaction between the copper and manganese oxide. For the CuO/γ‐Al 2 O 3 catalyst there are two reducible copper oxide species; α and β peaks are attributed to the reduction of highly dispersed copper oxide species and bulk CuO species, respectively. For the CuO‐MnO x /γ‐Al 2 O 3 catalyst, four reduction peaks are observed, α peak is attributed to the dispersed copper oxide species; β peak is ascribed to the bulk CuO; γ peak is attributed to the reduction of high dispersed CuO interacting with manganese; δ peak may be the reduction of the manganese oxide interacting with copper oxide. XPS results show that Cu + mostly existed on the working surface of the Cu‐Mn/γ‐Al 2 O 3 catalysts. The activity was promoted by Cu with positive charge which was formed by means of long path exchange function between CuOMn. These results indicate that there is synergistic interaction between the copper and manganese oxide, which is responsible for the high activity of CO 2 hydrogenation.