The influence of the preparation methods of Co-Al layered double hydroxides (LDHs) on the structural and catalytic properties of Co-Al mixed oxides for benzene total oxidation was investigated. Various Co-Al LDHs were synthesized via constant pH precipitation, decreasing pH precipitation, and urea homogeneous precipitation. The synthesized samples were characterized by using N₂ physical adsorption, ICP, XRD, TG–DTA, SEM, and H₂-TPR. The characterization results showed that calcination of Co-Al LDHs gave rise to Co-Al mixed oxides consisting of Co(Co, Al)₂O₄ spinel as the main phase, which showed relatively small crystallite size and high specific surface area, i.e., ~12 nm, 90–100 m² g _cat ⁻¹ . The highest catalytic activity was obtained on the Co-Al mixed oxide prepared by decreasing pH precipitation, followed by that prepared by constant pH precipitation, while the Co-Al mixed oxide prepared by urea homogeneous precipitation was much less active. The activity difference can be related to the different reducibility of Co³⁺ species in Co(Co, Al)₂O₄ spinel.

研究了Co-Al层状双氢氧化物（LDHs）的制备方法对Co-Al混合氧化物对苯全氧化的结构和催化性能的影响。通过恒定的pH沉淀，降低的pH沉淀和尿素均匀沉淀合成了各种Co-Al LDH。使用N ₂物理吸附，ICP，XRD，TG-DTA，SEM和H ₂ -TPR对合成样品进行表征。表征结果表明，Co-Al LDHs的煅烧产生了以Co（Co，Al）₂ O ₄尖晶石为主相的Co-Al混合氧化物，其晶粒尺寸较小，比表面积较高，即〜12 nm，90–100 m ²  g_猫 ^-1 。通过降低pH沉淀制备的Co-Al混合氧化物获得了最高的催化活性，随后通过恒定pH沉淀获得的催化活性最高，而通过尿素均相沉淀制备的Co-Al混合氧化物的活性低得多。活性差异可能与Co（Co，Al） ₂ O ₄尖晶石中Co ³⁺种类的不同还原性有关。