还原-氧化预处理对Co_3O_4催化分解N_2O性能的影响

采用液相沉淀法制备了Co_3O_4催化剂,并对其进行还原-氧化预处理制得Co_3O_4-RO。通过XRD、N_2-physisorption、Raman、H_2-TPR、XPS和O_2-TPD等技术对催化剂进行表征,在连续流动微反应装置上考察了催化剂催化分解N_2O性能。结果表明,经过还原-氧化预处理,与Co_3O_4催化剂相比,Co_3O_4-RO结晶度变差,晶粒粒径减小,尤其是尖晶石结构重构过程削弱了Co-O键,增强了催化剂表面的氧物种脱附能力,降低了催化分解N_2O反应的活化能,因而显著提高了催化剂的催化活性。同时,Co_3O_4-RO对原料气中的O_22%(体积分数)和H_2O 2. 3%(体积分数)表现出较强的耐受性。

Effect of reduction-oxidation pretreatment on the catalytic performance of Co3O4 catalyst in N2O decomposition

In this paper, Co₃O₄ catalysts were prepared by the liquid precipitation method, and further was subjected to reduction-oxidation pretreatment to obtain Co₃O₄-RO. The catalysts were characterized by XRD, N₂-physisorption, Raman, H₂-TPR, XPS and O₂-TPD. Their catalytic activities in N₂O decomposition were tested on a fixed-bed continuous flow microreactor. The results show that both the crystallinity and the crystallite size of Co₃O₄-RO decrease in comparison with Co₃O₄. Especially the structural reconstruction resulted from the reduction-oxidation pretreatment weakens the Co-O bond and enhances the oxygen desorption capacity on the catalyst surface, which endows the Co₃O₄-RO a lower activation energy. Thus the catalytic activity of the Co₃O₄-RO in N₂O decomposition increases significantly. At the same time, Co₃O₄-RO shows strong resistance to O₂ (2% in feed)and H₂O (2.3% in feed).