Ce-Zr物质的量比对Ru-Cex Zr1-xO2催化剂的性质及其湿式氧化苯酚性能的影响

Received :2018-04-04;Revised :2018-06-03. *Corresponding author.E-mail :xiaoyong @https://www.360docs.net/doc/c94806133.html, ,huaiqianlu @https://www.360docs.net/doc/c94806133.html,. Ce /Zr 物质的量比对Ru /Ce x Zr 1-x O 2催化剂的性质

及其湿式氧化苯酚性能的影响

赵 宁1,2,肖 勇1,*,鲁怀乾1,*,侯 博1,李德宝1,贾丽涛1

(1.中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原 030001;2.中国科学院大学,北京 100049)

摘 要:采用溶胶凝胶法制备了系列不同Ce /Zr 物质的量比的Ru /Ce x Zr 1-x O 2催化剂,通过X 射线衍射(XRD )二氮气吸附-脱附二拉曼(Raman )光谱二储氧能力(oxygen storage capacity ,OSC )二热重(TG )以及吡啶红外(Py-FTIR )等手段对其进行了表征,考察了该催化剂在湿式氧化苯酚反应中的性能三结果表明,ZrO 2可与CeO 2形成固溶体;随着ZrO 2掺杂量的增加,Ce x Zr 1-x O 2固溶体的OSC 值增大三相比于CeO 2,掺杂ZrO 2后催化剂表面的L 酸量明显增多三催化剂湿式氧化(catalytic wet air oxidation ,CWAO )性能与OSC 和表面酸性均有密切的关系:催化剂表面的L 酸有利于苯酚氧化生成CO 2,而OSC 过高会导致催化剂表面积炭,使催化剂失活三当ZrO 2掺杂量为25%时,在160?二2MPa 纯氧条件下,催化氧化苯酚5h 后,苯酚转化率和总有机碳(total organic carbon ,TOC )去除率分别为100%和99%,说明该催化剂具有优异的苯酚氧化性能三

关键词:催化湿式氧化;铈锆固溶体;苯酚;储氧性能;酸性;积炭

中图分类号:O 625.31+2 文献标识码:A

Effect of Ce /Zr molar ratio on the catalytic performance of Ru /Ce x Zr 1-x O 2in the wet air oxidation of phenol

ZHAO Ning 1,2,XIAO Yong 1,*,LU Huai-qian 1,*,HOU Bo 1,LI De-bao 1,JIA Li-tao 1(1.State Key Laboratory of Coal Conversion ,Institute of Coal Chemistry ,Chinese Academy of Sciences ,Taiyuan 030001,China 2.University of Chinese Academy of Sciences ,Beijing 100049,China )Abstract :A series of Ce x Zr 1-x O 2catalysts with different Ce /Zr molar ratios were prepared by sol-gel method and characterized by X-ray diffraction (XRD ),nitrogen sorption ,Raman spectra ,oxygen storage capacity (OSC ),thermogravimetry (TG )and pyridine adsorption infrared (Py-FTIR )spectra ;the performance of Ce x Zr 1-x O 2in catalytic wet air oxidation (CWAO )of phenol was investigated.The results demonstrate that Ce x Zr 1-x O 2solid solution is formed by doping ZrO 2in CeO 2and the OSC value of Ce x Zr 1-x O 2increases with an increase in the content of ZrO 2.In comparison with pure CeO 2,Ce x Zr 1-x O 2solid solution has more Lewis acid sites.The catalytic activity of Ce x Zr 1-x O 2is related to both OSC and surface acidity ;the Lewis acid sites are favorable for the complete oxidation of phenol ,whereas high OSC may promote the carbonaceous deposition that leads to catalyst deactivation.The Ru /Ce 0.75Zr 0.25O 2catalyst exhibits high activity in phenol oxidation ;after reaction for 5h at 160?and 2MPa O 2,phenol conversion and total organic carbon (TOC )rate reach 100%and 99%,respectively.Key words :catalytic wet air oxidation ;Ce-Zr solid solution ;phenol ;oxygen storage capacity ;acidity ;carbon deposit

催化湿式氧化法(Catalytic wet air oxidation ,CWAO )是处理高COD 二高氨氮二高色度等难降解有

毒有害工业废水的有效方法之一[1,2]三该方法在高温高压下利用O 2作为氧化剂,对有机物进行氧化

分解,使之转变为CO 2二N 2二水等无毒无害成分,具有适用范围广二二次污染少等优点,但该方法通常需

要较高的温度和压力,能耗大且对设备要求较

高[3-5]三开发高效二稳定催化剂缓和反应条件二提升有机物降解速率成为近年来研究热点之一三

在众多的CWAO 体系中,Ru /CeO 2具有优异的活性和稳定性二且价格相对便宜,被认为是最具应用前景的催化剂体系之一[6-10]三O 2的活化是CWAO 过程的限速步骤,CeO 2具有较强的活化O 2能力,但纯CeO 2在制备过程中易发生烧结,使CeO 2储氧能力下降三前人研究结果表明,通过掺杂ZrO 2可以同时提高CeO 2的热稳定性和储氧能力(Oxygen Storage Capacity ,OSC ),从而加快反应速率[11,12]三Li 等[13]通过掺杂ZrO 2形成Ru /Ce x Zr 1-x O 2固溶体第46卷第8期2018年8月燃 料 化 学 学 报Journal of Fuel Chemistry and Technology Vol.46No.8Aug.2018

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