Enhanced catalytic performance for CO oxidation and preferential CO oxidation over CuO/CeO_2 catalysts synthesized from metal organic framework: Effects of preparation methods

摘要

In this paper, CuO/CeO2 catalysts derived from Ce-BTC metal organic framework as the precursor were synthesized by various methods (in-situ synthesis method, mechanical mixing method and impregnation method). The precursors and catalysts were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), N-2 adsorption-desorption, H-2-temperature program reduction (H-2-TPR), inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS). It was found that the preparation methods strongly affected the low temperature reduction behavior and oxygen vacancies of CuO/CeO2 catalysts. The CuCeO-ETH catalyst showed excellent catalytic activity for CO oxidation (T-100 = 100 degrees C). Meanwhile, a broad temperature window to match CO conversion and selectivity higher than 98% at the same time appeared for preferential CO oxidation. In addition, the CuCeO-ETH catalyst displayed high reaction stability and CO catalytic performance for CO oxidation and preferential CO oxidation even after three cycles. The addition of H2O and CO2 in the stream caused a lightly decrease in the CO conversion. The CuCeO-ETH catalyst still maintains a CO conversion of 100% at 130 degrees C. The improved catalytic performance for CO oxidation and preference CO oxidation could be attributed to easily reducible surface copper species, more Cu+ oxygen vacancies and surface lattice oxygen. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.