Cu-based spinel catalysts CuB2O4 (B = Fe, Mn, Cr, Ga, Al, Fe0.75Mn0.25) for steam reforming of dimethyl ether Original Research Article

Cu-based spinel-oxides CuB2O4 (B = Fe, Mn, Cr, Ga, Al, or Fe0.75Mn0.25) were synthesized via a sol–gel method and subsequent solid-state reaction. The spinels mechanically mixed with γ-Al2O3 were evaluated for production of hydrogen from dimethyl ether steam reforming (DME SR). The reduction behavior and crystal property of these spinel-oxides, and the Cu oxidation state in spinel catalysts were investigated by temperature-programmed reduction, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The reduced phases of the Cu-based spinel catalysts that strongly affected the catalytic activity and durability were composed of metallic copper with metal oxides (MnO (B = Mn), Cr2O3 (B = Cr), and Al2O3 (B = Al)) or with spinels (CuGa2O4 (B = Ga), Fe3O4 (B = Fe), and MnFe2O4 (B = Fe0.75Mn0.25). The stability of B metal oxides and the interaction between copper species and B metal oxides significantly contributed to the reforming performance.