The highly efficient removal of HCN over Cu8Mn2/CeO2 catalytic material.

Abstract

In this work, porous CeO2 flower-like spheres loaded with bimetal oxides were prepared to achieve effective removal of HCN in the lower temperature region of 30–150 °C. Among all samples, the CeO2 loaded with copper and manganese oxides at the mass ratio of 8/2 (Cu8Mn2/CeO2) exhibited the highest catalytic activity: the HCN removal rate was nearly 100% at 90 °C at the conditions of 120 000 h−1 and 5 vol% H2O, the catalytic activity of which was higher than for other reported catalysts. The introduction of MnOx could improve the dispersion of CuO particles and increase the total acid sites of the prepared samples. It was proved that the synergy between CuO and MnOx, the chemisorption oxygen, the oxygen vacancies, the Cu2+ and Mn4+ all played an important role in determining the good catalytic activity of the prepared samples. NH3-TPD analysis indicated the introduction of MnOx promoted the conversion of NH3 and N2 selectivity by increasing the acid sites of the sample. According to the C, N balance data and FT-IR results, when the temperature was below 30 °C, the removal of HCN over Cu8Mn2/CeO2 was mainly by chemisorption and the HCN breakthrough behaviors corresponded to the Yoon and Nelson's model. When temperature was above 120 °C, the HCN was totally removed by catalytic hydrolysis and catalytic oxidation.