MIL-101前驱体制备MnO_(x)-Cr_(2)O_(3)催化剂及其对苯的催化氧化性能  

Preparation of MnO_(x)-Cr_(2)O_(3) from MIL-101 precursor and its catalytic oxidation performance for benzene

作　　者：郑钦中 武晓峰[1] 陈运法[1,3] ZHENG Qinzhong;WU Xiaofeng;CHEN Yunfa(State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;School of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Center for Excellence in Regional Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen 361021,China)

机构地区：[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

出　　处：《中国粉体技术》2021年第4期54-62,共9页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:51672273。

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MnO_(x)-Cr_(2)O_(3)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MnO_(x)-Cr_(2)O_(3)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3447 m^(2)/g;MnO_(x)-Cr_(2)O_(3)复合催化剂,比表面积为89.30 m^(2)/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;MnO_(x)-Cr_(2)O_(3)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。Using chromium nitrate,terephthalic acid and hydrofluoric acid as raw materials,MIL-101(Cr)was prepared by hydrothermal method.The MnO_(x)-Cr_(2)O_(3) composite catalysts were subsequently prepared by high temperature pyrolysis by preimpregnation with KMnO4 and reduction with H2O2.The catalytic activity of MnO_(x)-Cr_(2)O_(3) 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 3447 m^(2)/g after multiple activation with methanol.Specific surface area of high activity MnO_(x)-Cr_(2)O_(3) catalyst support is 89.30 m^(2)/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 MnO_(x)-Cr_(2)O_(3) 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 MnO_(x)-Cr_(2)O_(3) can inhibit the release of toxic Cr element.

关 键 词：铬氧化物 锰氧化物 催化氧化 挥发性有机物 

分 类 号：TB3[一般工业技术—材料科学与工程]