Promoting effect of Cu-doping on catalytic activities and SO2 resistance of porous CeO2 nanorods for H2S selective oxidation

Abstract A facile procedure of doping copper species into CeO2 lattices was reported here to prevent ceria from deactivation and to offer additional active sites for H2S selective oxidation. Among the prepared catalysts, the porous 10Cu/Ce nanorods with well-defined (100) and (110) reactive planes displays excellent catalytic performance, exhibiting H2S conversion and sulfur selectivity of 100% at 220 °C, which is higher than those of the most reported Ce-based catalysts. More importantly, the electron transfer from Cu+ to Ce4+ suppresses the transfer of electron from SO2 to Ce4+, leading to inhabitation of SO2 oxidation to surface SO4 which could deactivate catalyst. Overall, the results of systematic experimental and theoretical studies prove that the copper doping effectively promotes the formation of oxygen vacancies and resistance against SO2 poisoning. Furthermore, through in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) investigation and density functional theory (DFT) calculations, the reaction intermediates in H2S selective oxidation and mechanism of SO2 resistance over the Cu-doped CeO2 catalysts are revealed.