Synergistic effect of Cu2+ doping and sulfation in Cu-Ce-S, tolerance to H2O and SO2 and decomposition behaviors of ammonia salts

Abstract

A novel Cu-Ce-S nanocrystal catalyst for SCR of NOx was prepared via a simple one step method using PS as a template and CuSO4 as both S and Cu sources. Cu-Ce-S exhibited excellent SCR activity, N2 selectivity and tolerance to H2O and SO2, the NOx conversion for 3% Cu-Ce-S only decreased by 3% while the CeO2 decreased by 64% in the presence of H2O and SO2. Results of XRD, XPS, DRIFTS and TG showed that the Cu2+ were replaced a part of Ce4+ and dissolved in CeO2 lattice, which tended to link with the SO42−group in SCR process to effectively avoid poisoning of Ce4+ active sites. The circles of Cu2+ + e → Cu+ and Ce3+ - e → Ce4+ promoted the catalyst activity. The study of decomposition behavior of deposition species on catalyst surface under low operation temperature indicated that Cu2+ doping and sulfation could inhibit the formation of ammonium sulfate or bisulfate and promote their decomposition to relieve the catalyst inactivation caused by the block of active sites.