ABSTRACT

The Co_xO_y/AC catalysts were prepared by wet impregnation method for toluene oxidation removal from air. The thermal stability of cobalt nitrate and Co oxide on the activated carbon (AC) support surface was analysed by thermal analysis. The physicochemical properties of the prepared catalysts were characterised by XRD, SEM, H₂-TPR, and XPS. AC support with high specific surface area and developed pore structure can promote the dispersion of Co species on its surface to form highly dispersed Co oxide species. The participation of AC supports can promote the partial reduction of Co₃O₄ species to CoO species to coexist in the prepared Co_xO_y/AC catalyst. The Co²⁺/Co³⁺ ratio was significantly affected by the calcination temperature, and the appropriate Co²⁺/Co³⁺ ion pairs in the studied Co_xO_y/AC catalyst is helpful to the activity of O₂ molecules to form reactive oxygen species. The oxygen species composition on the catalyst surface is obviously affected by the calcination temperature, which plays an important role in toluene oxidation reaction. The studied Co_xO_y/AC catalysts exhibited excellent toluene oxidation removal performances. The conversion of toluene exceeded 97% and 99% at 240°C and 250°C, respectively, and maintained good stability within 700 min. That is to say, the concentration of toluene in the air can be reduced from 10,000 ppm to less than 40 ppm by using the Co_xO_y/AC catalyst.

摘要

Co _x O _y /AC 催化剂采用湿法浸渍法制备，用于氧化去除空气中的甲苯。通过热分析对活性炭 (AC) 载体表面上的硝酸钴和氧化钴的热稳定性进行了分析。通过XRD、SEM、H ₂ -TPR和XPS表征了所制备催化剂的物理化学性质。具有高比表面积和发达孔结构的活性炭载体可以促进Co物种在其表面的分散，形成高度分散的Co氧化物物种。AC载体的参与可以促进Co ₃ O ₄物种部分还原为CoO物种共存于制备的Co _x O _y /AC催化剂中。公司²⁺ /Co ³⁺比例受焙烧温度影响显着，所研究的Co _x O _{y /AC催化剂中合适的Co} ²⁺ /Co ³⁺离子对有利于O ₂分子形成活性氧的活性物种。催化剂表面氧物种组成受焙烧温度影响明显，对甲苯氧化反应起着重要作用。研究的 Co _x O _y/AC催化剂表现出优异的甲苯氧化去除性能。240℃和250℃时甲苯转化率分别超过97%和99%，并在700 min内保持良好的稳定性。也就是说，通过使用Co _x O _y /AC催化剂，可以将空气中的甲苯浓度从10000ppm降低到40ppm以下。