Reduction behaviors and catalytic properties for methanol steam reforming of Cu-based spinel compounds CuX2O4 (X=Fe, Mn, Al, La)

Abstract In this study, various Cu-based spinel compounds, i.e. , CuFe 2 O 4 , CuMn 2 O 4 , CuAl 2 O 4 and CuLa 2 O 4 , were fabricated by a solid-state reaction method. Reduction behaviors and morphological changes of these materials have been characterized by H 2 temperature-programmed reduction (H 2 -TPR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Moreover, the catalytic properties for steam reforming of methanol (SRM) of these Cu-based spinel compounds were investigated. H 2 -TPR results indicated that the reducibility of Cu-based spinel compounds was strongly dependent on the B-site component while the CuFe 2 O 4 catalyst revealed the lowest reduction temperature (190 °C), followed respectively by CuAl 2 O 4 (267 °C), CuMn 2 O 4 (270 °C), and CuLa 2 O 4 (326 °C). The reduced CuAl 2 O 4 catalyst demonstrated the best performance in terms of catalytic activity. Based on the SEM and XRD results, pulverization of the CuAl 2 O 4 particles due to gas evolution and a high concentration of nanosized Cu particles (≈50.9 nm) precipitated on the surfaces of the Al 2 O 3 support were observed after reduction at 360 °C in H 2 . The BET surface area of the CuAl 2 O 4 catalyst escalated from 5.5 to 13.2 m 2 /g. Reduction of Cu-based spinel ferrites appear to be a potential synthesis route for preparing a catalyst with high catalytic activity and thermal stability. The catalytic performance of these copper-oxide composites was superior to those of conventional copper catalysts.