刚玉型复合氧化物催化剂Cr1.3Fe0.7O3上二氯甲烷催化燃烧  

Catalytic combustion of dichloromethane over Cr_(1.3)Fe_(0.7)O_3 composite oxides

作　　者：宁想 张婷婷 邢金媛 陈家喜 李艳明 鲁继青[1] Ning Xiang;Zhang Tingting;Xing Jinyuan;Chen Jiaxi;Li Yanming;Lu Jiqing(Key Laboratory of the Ministry of Education for Advanced Catalysis Materials,College of Chemistry and Life Sciences,Zhejiang Normal University,Jinhua 321004,Zhejiang,China;Information Center,Zhejiang Normal University Library,Zhejiang Normal University,Jinhua 321004, Zhejiang,China)

机构地区：[1]浙江师范大学化学与生命科学学院,教育部先进催化材料重点实验室,浙江金华321004 [2]浙江师范大学图文信息中心,浙江金华321004

出　　处：《工业催化》2018年第12期30-38,共9页Industrial Catalysis

基　　金：国家自然科学基金(21643007;21773212);浙江省自然科学基金(LY17B030001)

摘　　要：通过溶胶-凝胶法合成一系列具有刚玉结构的Cr_(1.3)Fe_(0.7)O_3复合氧化物,在二氯甲烷催化燃烧反应中进行活性评价。结果表明,复合氧化物比单金属氧化物CrO_x和FeO_x具有更高的催化活性,其催化活性与氧化物的表面酸性和可还原性密切相关,二者在反应中协同作用。与高温焙烧样品相比,低温焙烧的Cr_(1.3)Fe_(0.7)O_3催化剂具有更高的比表面积、表面酸性和可还原性,催化性能更优。以表面酸性位数量为基础计算的催化剂转化频率(TOF)表明,各Cr_(1.3)Fe_(0.7)O_3催化剂活性相近(300℃时约2.3×10^(-3) s^(-1)～2.8×10^(-3) s^(-1)),表面酸性位上发生二氯甲烷分子吸附及C-Cl键断裂,是反应活性位。300℃时Cr^(6+)的TOF为9.3×10^(-3) s^(-1),Cr^(3+)的TOF为0.59×10^(-3) s^(-1),Cr^(6+)物种比Cr^(3+)物种具有更高的活性。A series of Cr 1.3 Fe 0.7 O 3 composite oxides with corundum structures were synthesized by sol-gel method and tested in catalytic combustion of dichloromethane(DCM).These oxides were much more active than monometallic CrO x and FeO x oxides.The catalytic performance was closely related to surface acidity and reducibility of the oxide,which showed clear synergistic effect in the reaction.Compared to those calcined at higher temperature,Cr 1.3 Fe 0.7 O 3 catalysts calcined at lower temperature had higher surface area,surface acidity and reducibility which were responsible for better catalytic performance.The similar average turnover frequencies(TOFs)for all the catalysts based on surface acidities(about 2.3×10-3 s-1-2.80x0E?SymboltB@0x0F10-3 s-1 at 300℃)suggested that surface acid sites were active sites for the reaction since they provided centers for DCM chemisorption and subsequent cleavage of C-Cl bond.Moreover,the calculation revealed that the high-valent Cr 6+species were more active than the Cr 3+(with a TOF of 9.3×10-3 s-1 versus 0.590x0E?SymboltB@0x0F10-3 s-1 at 300℃).

关 键 词：催化化学 CVOC催化燃烧 Cr1.3 Fe0.7 O3复合氧化物 刚玉结构 表面酸度 高价铬物种 

分 类 号：O643.36[理学—物理化学] X701[理学—化学]