LAUSR

Abstract The development of innovative treatment technology for HCN at low temperatures is vital for the control of HCN pollution. Here, a copper manganese oxide (Cu-Mn-O) catalyst was prepared for the decomposition of HCN at temperatures from 80 to 200 °C. The results showed that the Cu-Mn-O catalyst exhibited excellent catalytic performance for HCN conversion. X-ray photoelectron spectroscopy analysis revealed that Mn3+ manifested highly catalytic activity and was largely responsible for HCN decomposition. The N-contained products of HCN contained NH3, NO/NO2, N2O, and N2, thereby suggesting the concurrent catalytic oxidation and hydrolysis during HCN decomposition on the catalyst. The catalytic oxidation mechanism characterized by in situ diffuse reflectance infrared Fourier transform manifested that four N-contained intermediates (i.e., -CN, -NH2, =NH and -NCO) were produced; subsequent the oxidation of these intermediates resulted in the formation of final product and/or oxidative species NO+. The reaction of NO+ with the N-contained intermediates also generated the final conversion products. Catalytic intermediate formamide plays a critical role in the hydrolysis of HCN, and its hydrolysis leads to the formation of NH3. Multiple cycle experiments demonstrate the long-term stability of the Cu-Mn-O catalyst. These results indicate that catalytic decomposition of HCN based on the Cu-Mn-O catalyst at low temperatures may be an efficient approach for the treatment of tail gases containing HCN.