Promotional effects of Er incorporation in CeO2(ZrO2)/TiO2 for selective catalytic reduction of NO by NH3

A series CeO2(ZrO2)/TiO2 catalysts were modified with Er using a sol-gel method. The catalytic activity of the obtained catalysts in the selective catalytic reduction (SCR) of NO with NH3 was investigated to determine the appropriate Er dosage. The catalysts were characterized using X-ray diffraction, N-2 adsorption, NH3 temperature-programmed desorption, H-2 temperature-programmed reduction, photoluminescence spectroscopy, electron paramagnetic resonance spectroscopy, and X-ray photoelectron spectroscopy. The results showed that the optimum Er/Ce molar ratio was 0.10; this catalyst had excellent resistance to catalyst poisoning caused by vapor and sulfur and gave more than 90% NO conversion at 220-395 degrees C and a gas hourly space velocity of 71 400 h(-1). Er incorporation increased the Ti3+ concentrations, oxygen storage capacities, and oxygen vacancy concentrations of the catalysts, resulting in excellent catalytic performance. Er incorporation also decreased the acid strength and inhibited growth of TiO2 and CeO2 crystal particles, which increased the catalytic activity. The results show that high oxygen vacancy concentrations and oxygen storage capacities, large amounts of Ti3+ and low acid strengths give excellent SCR activity. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.