CAJ | 학술논문

对Cu/Ag-OMS-2(OMS-2为锰氧八面体分子筛)催化剂中铜物种在热处理过程中的分散情况和存在形式进行了研究,通过X射线衍射、扫描电子显微镜表征手段分别考察了焙烧温度、焙烧时间和活性组分负载量不同时催化剂中铜物种的表面状态, 并分析了铜物种表面状态对催化氧化羰基化合成碳酸二甲酯反应的影响.结果表明,在热处理过程中,铜物种以片状形式均匀排列堆积,有利于反应物的吸附,有利于催化剂活性的提升;活性组分主要以氯化铜(CuCl)形式存在,受热部分分解为含有Cu+和Cu2+的铜氧化物6CuO·Cu2O,两种不同价态的铜物种的存在促进反应物的解离吸附,有利于提升催化活性.较适宜的催化剂热处理条件为:CuCl的负载量为25%,焙烧温度为500℃,焙烧时间为5 h,催化合成碳酸二甲酯的收率最高可达85%.
대Cu/Ag-OMS-2(OMS-2위맹양팔면체분자사)최화제중동물충재열처리과정중적분산정황화존재형식진행료연구,통과X사선연사、소묘전자현미경표정수단분별고찰료배소온도、배소시간화활성조분부재량불동시최화제중동물충적표면상태, 병분석료동물충표면상태대최화양화탄기화합성탄산이갑지반응적영향.결과표명,재열처리과정중,동물충이편상형식균균배렬퇴적,유리우반응물적흡부,유리우최화제활성적제승;활성조분주요이록화동(CuCl)형식존재,수열부분분해위함유Cu+화Cu2+적동양화물6CuO·Cu2O,량충불동개태적동물충적존재촉진반응물적해리흡부,유리우제승최화활성.교괄의적최화제열처리조건위:CuCl적부재량위25%,배소온도위500℃,배소시간위5 h,최화합성탄산이갑지적수솔최고가체85%.
The dispersion state and the existence form of copper species in Cu∕Ag-OMS-2 catalysts were in-vestigated. The surface states of copper species at different calcination temperatures, different calcination times and different CuCl loadings were studied by X-ray diffraction and scanning electron microscope. The effects of surface state of copper species on catalytic performance of Cu∕Ag-OMS-2 in oxidative carbonylation of methanol were also determined. The results show that the copper species existed in thin slice form and dis-perse well on the catalyst surface after calcination treatment,which is beneficial to adsorption of the reactants and catalytic activities;the active species exist mainly in the form of CuCl, and partly decompose into 6CuO· Cu2O including Cu+and Cu2+ species; the mixed valence of copper species is advantageous to good catalytic performance. The optimal preparation condition of Cu∕Ag-OMS-2 catalysts is calcined at 500℃ for 5 h and the CuCl loading of 25%, and the yield of dimethyl carbonate for corresponding catalyst reaches 85%.