Soft-chemical synthesis and catalytic activity of Ni-Al and Co-Al layered double hydroxides (LDHs) intercalated with anions with different charge density
Soft-chemical synthesis and catalytic activity of Ni-Al and Co-Al layered double hydroxides (LDHs) intercalated with anions with different charge density
复制标题
DOI：
10.1016/j.jascer.2014.06.002
复制
发表时间：
2014-09
影响因子：
2.3
通讯作者：
T. Takei;A. Miura;N. Kumada
中科院分区：
文献类型：
--
作者：
T. Takei;A. Miura;N. Kumada
采用离子交换和共沉淀法分别制备了十二烷基硫酸酯(C12H25SO4−，DS)、丁二酸二乙酯([COOC2H3EtBu]2C2H3SO3−，D2ES)和多钨酸盐(H2W12O4210−，HWO)三种阴离子分子插层Co-Al和Ni-Al层状双氢氧化物(LDHs)。在DS和D2ES作为插层剂的情况下，插层后的LDHs仍保持较高的结晶度。在HWO的情况下，通过离子交换和共沉淀可以得到插层LDHs，但结晶度下降；但在离子交换样品中检测到未反应的LDH，并在共沉淀过程中产生了一些不需要的相，如氢氧化物和焦绿石。采用离子交换法制备的插层水滑石Ni-Al样品的最大比表面积和孔容分别为74×10~2/g和0.174×m~2/g。在Co-Al和Ni-Al LDHs中，DS、D2ES和HWO在层间距中的占有率分别约为0.3-0.4、0.5-0.6和0.1-0.2。催化活性分析表明，DS插层Ni-Al LDH样品对环己醇转化为环己酮表现出较好的催化活性。
Co-Al and Ni-Al layered double hydroxides (LDHs) intercalated with three types of anionic molecules, dodecylsulfate (C12H25SO4−, DS), di-2-ethylsulfosuccinate ([COOC2H3EtBu]2C2H3SO3−, D2ES), and polytungstate (H2W12O4210−, HWO) were prepared by means of ion-exchange and co-precipitation processes. With the use of DS and D2ES as intercalation agents, high crystallinity was maintained after intercalation into the LDHs. In the case of HWO, the intercalated LDHs could be obtained by ion-exchange as well as co-precipitation with a decline in the crystallinity; however, unreacted LDH was detected in the ion-exchange samples, and some unwanted phases such as hydroxide and pyrochlore were generated by the co-precipitation process. The maximum specific surface area and pore volume of the Ni-Al sample with intercalated HWO, prepared by the ion-exchange process were 74 m2/g and 0.174 mL/g, respectively. The occupancies of DS, D2ES, and HWO within the interlayer space were approximately 0.3–0.4, 0.5–0.6, and 0.1–0.2, respectively, in the Co-Al and Ni-Al LDHs. Analysis of the catalytic activity demonstrated that the DS-intercalated Ni-Al LDH sample exhibited relatively good catalytic activity for conversion of cyclohexanol to cyclohexanone.