水热合成Co3O4的制备参数调变及其催化分解N2O性能

以十六烷基三甲基溴化胺（CTAB）为模板剂，通过调变CTAB浓度水热合成了氧化钴前驱体，焙烧制得棒状形貌的Co₃O₄，在其表面浸渍K₂CO₃溶液制得K改性的Co₃O₄催化剂，用于N₂O分解。用X射线衍射（XRD）、N₂物理吸附（BET）、扫描电镜（SEM）、X射线光电子能谱（XPS）、H₂程序升温还原（H₂-TPR）和O₂程序升温脱附（O₂-TPD）等技术对催化剂进行了表征，考察了CTAB/钴及尿素/钴物质的量比等制备参数对Co₃O₄催化分解N₂O活性的影响。结果表明，CTAB浓度为0.05 mol/L、CTAB/钴离子物质的量比为1、尿素/钴离子物质的量比为4时，所制备的Co₃O₄催化剂具有较高的N₂O分解活性，而K改性可以进一步提升其催化性能。K改性的Co₃O₄在有氧有水气氛中400℃下进行N₂O分解反应，50 h后N₂O转化率仍保持在91%以上。

Effect of preparation parameters on the catalytic performance of hydrothermally synthesized Co3O4 in the decomposition of N2O

With hexadecyl trimethyl ammonium bromide (CTAB) as the template, cobaltosic oxide precursors were hydrothermally synthesized. Co₃O₄ catalysts were then prepared by calcining the cobaltosic oxide precursors, which was further modified by impregnation with K₂CO₃ solution and used in the decomposition of N₂O. The catalysts were characterized by means of X-ray diffraction (XRD), nitrogen physisorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H₂-TPR), and oxygen temperature-programmed desorption (O₂-TPD); the effect of CTAB concentration, CTAB/cobalt molar ratio and urea/cobalt molar ratio on the catalytic activity of Co₃O₄ was investigated. The results indicated that the Co₃O₄ catalyst prepared by using 0.05 mol/L CTAB solution, with a CTAB to cobalt molar ratio of 1 and a urea to cobalt molar ratio of 4, exhibits high activity in N₂O decomposition. The catalytic performance of Co₃O₄ can be further enhanced by modifying with K. Over the 0.02K/Co₃O₄ catalyst, the N₂O conversion remains over 91% at 400°C after conducting the N₂O decomposition reaction for 50 h in the presence of oxygen and steam.