郑钦中1,2， 武晓峰1， 陈运法1,3
（1. 中国科学院 过程工程研究所； 多相复杂系统国家重点实验室， 北京 100190；2. 中国科学院大学 化学工程学院，北京 100049；3. 中国科学院 城市环境研究所； 区域大气环境研究卓越创新中心， 福建 厦门 361021）
DOI:10.13732/j.issn.1008-5548.2021.04.007
收稿日期： 2021-04-26， 修回日期：2021-05-08，在线出版时间：2021-06-01 09:40。
基金项目：国家自然科学基金项目，编号：51672273。
第一作者简介：郑钦中(1995—)，男，硕士研究生，研究方向为纳米结构材料。E-mail：zheng-qz@qq.com。
通信作者简介：武晓峰(1978—)，男，博士，研究员，博士生导师，研究方向为环境净化材料。E-mail：wxftsjc@ipe.ac.cn。
摘要：以硝酸铬、对苯二甲酸、氢氟酸为原料，水热法制备MIL-101(Cr);经KMnO4预浸渍、H2O2还原对其进行MnOx负载，再经热解制备MnOx-Cr2O3复合催化剂;借助BET、XRD、SEM、TEM、XPS等测试手段，研究不同MnOx负载量的MnOx-Cr2O3复合催化剂对苯的催化氧化活性。结果表明:氢氟酸的添加量对MIL-101(Cr)孔结构影响显著，添加125μL的氢氟酸制备的MIL-101(Cr)具有最佳的多孔性，经甲醇多次活化后，其比表面积达到3 447 m2/g;MnOx-Cr2O3复合催化剂，比表面积为89.30 m2/g，远大于市售的Cr2O3载体的，对苯催化氧化的活性T90%为280℃;MnOx负载量质量分数为5%时，催化苯的T90%为266℃，但增加MnOx负载量对复合催化剂的催化活性影响不大;MnOx-Cr2O3复合催化剂的高催化氧化活性归因于Mn与Cr之间的电子迁移与表面晶格氧含量高;其良好催化活性和无毒MnOx包覆可抑制毒性Cr元素析出。
关键词：铬氧化物；锰氧化物；催化氧化；挥发性有机物
Abstract：Using chromium nitrate,terephthalic acid and hydrofluoric acid as raw materials,MIL-101(Cr) was prepared by hydrothermal method.The MnOx-Cr2O3 composite catalysts were subsequently prepared by high temperature pyrolysis by preimpregnation with KMnO4 and reduction with H2O2.The catalytic activity of MnOx-Cr2O3 composite catalysts to benzene oxidation with different MnOx loading were characterized by BET、XRD、SEM、TEM、XPS.The results show that the addition of hydrofluoric acid plays a significant role in the pore structure of MIL-101(Cr) with high specific surface area.The MIL-101(Cr) prepared by adding 125μL hydrofluoric acid has the best porosity,and its specific surface area reaches 3 447 m2/g after multiple activation with methanol.Specific surface area of high activity MnOx-Cr2O3 catalyst support is 89.30 m2/g,much higher than the commercial Cr2O3 support,andshows high catalytic activity for benzene oxidation (T90%=280℃).When the MnOx loading is 5%,the T90% of benzene being catalyzed is 266℃,but increasing the MnOx loading has little effect on the catalytic activity of the composite catalysts.The high catalytic activity of MnOx-Cr2O3 for benzene oxidation is attributed to the electron transfer between Mn and Cr,and the high surface lattice oxygen content.Good catalytic activity and non-toxic MnOx coating of MnOx-Cr2O3 can inhibit the release of toxic Cr element.
Keywords：chromium oxide; manganese oxide; catalytic oxidation; volatile organic compounds
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