tailieunhanh - Characterization of CaO-CuO-CeO2 mixed oxide synthesized by the impregnation and investigation of its reusability

The results indicated that there were three CuO species in the mixed oxide: the finely dispersed CuO species on the surface of CeO2, the Ce1-x-yCuxCayO2-δ solid solution and the bulk CuO. Most of particles have clear morphology with relatively uniform size in the range of 30 - 50 nm and the BET surface area was m2 /g. After three times of use, the catalytic activity of CaO-CuO-CeO2 mixed oxide was still relatively high and much higher than the mixed oxide CaO-CeO2 and CuO-CeO2. | Vietnam Journal of Science and Technology 55 (4) (2017) 429-436 DOI: CHARACTERIZATION OF CaO-CuO-CeO2 MIXED OXIDE SYNTHESIZED BY THE IMPREGNATION AND INVESTIGATION OF ITS REUSABILITY Hoang Thi Huong Hue1, *, Nguyen Van Quang2, *, Nguyen Thi Anh2 1 Faculty of Chemistry, University of Science, VNU, 19 Le Thanh Tong, Hoan Kiem, Hanoi 2 Institute of Environmental Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Hanoi * Email: ; hoangthihuonghue@ Received: 1 December 2016; Accepted for publication: 2 July 2017 ABSTRACT CaO-CuO-CeO2 mixed oxide was prepared by the impregnation method and used as the catalyst for the complete decomposition of phenol in the presence of hydrogen peroxide. The CaO-CuO-CeO2 mixed oxide were characterized by XRD, SEM, BET, H2-TPR and Raman spectroscopy. The results indicated that there were three CuO species in the mixed oxide: the finely dispersed CuO species on the surface of CeO2, the Ce1-x-yCuxCayO2-δ solid solution and the bulk CuO. Most of particles have clear morphology with relatively uniform size in the range of 30 - 50 nm and the BET surface area was m2/g. After three times of use, the catalytic activity of CaO-CuO-CeO2 mixed oxide was still relatively high and much higher than the mixed oxide CaO-CeO2 and CuO-CeO2. Keywords: CaO-CuO-CeO2 mixed oxide, phenol oxidation, impregnation method. 1. INTRODUCTION Recently, several works have shown that CeO2 is one of effective catalysts for many oxidation reactions [1, 2]. However, after a certain period (especially in high temperature conditions) its reactivity would decrease as CeO2 is sintered. The sintering process of CeO2 is greatly reduced when CeO2 is doped because the doping of other metal ions will form a solid solution with CeO2. The formation of a solid solution leads to an increase in the heat durability of the system. Moreover, the addition of metal cations with oxidation numbers smaller than +4 on CeO2 .