Kim Kyoung-Hun, Kim Jeong-Rang, Ihm Son-Ki
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea.
J Hazard Mater. 2009 Aug 15;167(1-3):1158-62. doi: 10.1016/j.jhazmat.2009.01.110. Epub 2009 Feb 6.
The mixed oxide (Ce(0.65)Zr(0.35)O(2)) prepared by supercritical synthesis was applied as a support of transition metal (Mn, Fe, Co, Ni, and Cu) oxide catalysts for catalytic wet oxidation (CWO) of phenol in view of their higher thermal stability, better oxygen storage capacity, and higher surface area. The prepared catalysts showed an enhanced catalytic activity for CWO of phenol due to the excellent redox properties of ceria-zirconia mixed oxide. Among the prepared catalysts, the CuO(x)/Ce(0.65)Zr(0.35)O(2) was the most effective catalyst in view of catalytic activity and CO(2) selectivity. The leached copper ions seem to contribute to the higher conversion of phenol over the CuO(x)/Ce(0.65)Zr(0.35)O(2) via homogeneous catalysis. The characterization with XPS, XANES, and TPR experiments confirmed that the active copper species in the CuO(x)/Ce(0.65)Zr(0.35)O(2) is highly dispersed Cu(2+) clusters. Although the MnO(x)/Ce(0.65)Zr(0.35)O(2) showed a high conversion of phenol and TOC, the converted phenol was mainly changed to carbon deposits on the surface of catalyst resulting in catalyst deactivation.
鉴于超临界合成制备的混合氧化物（Ce(0.65)Zr(0.35)O(2)）具有更高的热稳定性、更好的储氧能力和更大的表面积，将其用作过渡金属（Mn、Fe、Co、Ni和Cu）氧化物催化剂的载体，用于苯酚的催化湿式氧化（CWO）。由于铈锆混合氧化物具有优异的氧化还原性能，所制备的催化剂对苯酚的CWO表现出增强的催化活性。在所制备的催化剂中，就催化活性和CO(2)选择性而言，CuO(x)/Ce(0.65)Zr(0.35)O(2)是最有效的催化剂。浸出的铜离子似乎通过均相催化作用，有助于提高CuO(x)/Ce(0.65)Zr(0.35)O(2)上苯酚的转化率。XPS、XANES和TPR实验表征证实，CuO(x)/Ce(0.65)Zr(0.35)O(2)中的活性铜物种是高度分散的Cu(2+)簇。尽管MnO(x)/Ce(0.65)Zr(0.35)O(2)显示出苯酚和总有机碳的高转化率，但转化的苯酚主要变成催化剂表面的碳沉积物，导致催化剂失活。
