Facile synthesis of new efficient Cu/MnO2 catalysts from used battery for CO oxidation

Abstract

In this work, the MnO2 materials were successfully synthesized by reductive acidic leaching of waste material of used Zn-Mn batteries, which were next used as supports for copper catalysts and applied in carbon monoxide oxidation. The materials were characterized in detailed by X-ray photoelectron spectroscopic (XPS), Energy dispersive X-ray spectroscopy (EDX), H2-temperature program reduction (H2-TPR), X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption and scanning electron microscope (SEM). When Cu species was dropped on MnO2, the catalytic activity test showed that all doped MnO2 catalysts exhibit much enhanced CO oxidation activity. It was found that the catalyst 7Cu/MnO2 (Cu-loading: 7wt%) was efficient for oxidizing carbon monoxide. The 7Cu-MnO2 catalyst showed a high catalytic activity and excellent stability with a complete CO conversion temperature (T100) of 120°C, which was attributed to low temperature reduction ability, Cu2+, smaller particle size and a high quantity of surface active oxygen species and oxygen vacancies. The high catalytic activity suggested that Cu species doping could make the CO reaction with lattice oxygen together with the formation of oxygen vacancies, which is beneficial to CO oxidation. Further, the effect of water vapor on catalytic activity was also examined. The introduction of water vapor to the feedstock induced a very little negative effect on CO oxidation over 7Cu/MnO2 catalyst. The facile and promising strategy employed in this study could be expanded to the fabrication of other catalysts with the green reuse of used batteries as supports.