Cu doped MnO2/γ-Al2O3: a facile and efficient catalyst for the degradation of Na2S in waste water under ambient conditions

A series Cu decorated MnO2/γ-Al2O3 catalysts (Cu load, 1%, 3% and 5%) was fabricated by facile co-impregnation method, and investigated for the catalytic oxidative removal Na2S in waste water. Compared with MnO2/γ-Al2O3, the catalytic activity and stability of Cu-MnO2/γ-Al2O3, was enhanced by modifying with Cu element. XRD, SEM, BET, H2-TPR and XPS were carried out to characterize these catalyst. XRD and BET show the Cu successfully decorated on the MnO2/γ-Al2O3, and catalyst’s pristine structure are well maintained. SEM shows that the doped Cu species benefits to the uniform dispersion of Mn species, H2-TPR suggests that the reodox capacity of Cu decorated catalysts were improved after doping with Cu, and XPS shows that doped Cu produces higher concentration of Mn4+ and Oads (surface active oxygen species), also expediting the redox cycling between Mn4+/Mn3+ and the promote the Oads production, which resulting in the enhancement of redox properties. Hence, 3%Cu-MnO2/γ-Al2O3 catalyst could achieve 97.5% degradation of Na2S in waste water at room conditions in 2 h, by the help of air, this result is superior to other published work.