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采用沉积沉淀法制备了CO低温氧化 Au/α-Fe2O3催化剂,利用 X 射线衍射(XRD)、X 射线光电子能谱(XPS)、BET 比表面测定、程序升温还原(H2-TPR)等表征技术,对比了制备过程 pH 值的微小变化、焙烧及光线照射对催化剂结构及催化性能的影响,探明了 Au/α-Fe2O3催化剂的活性物种。结果表明,110 ℃处理的 Au/α-Fe2O3催化剂表面同时存在 Au3+、Au0以及过渡态 Auδ+(0<δ<1),它们对 CO 氧化的活性顺序为 Au3+>Auδ+>Au0;pH 值为 8 条件下制备的催化剂 Au3+含量高、比表面积大,催化性能最好;高温焙烧使氧化态金还原的同时也使载体比表面积严重缩小,催化活性显著下降;紫外线照射可以引起 Au3+的逐渐还原以及 Au0 颗粒的生长,其催化失活作用弱于高温焙烧。
The low temperature oxidized Au / α-Fe2O3 catalyst was prepared by deposition precipitation method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area measurement and H2- The effects of small changes of pH value, calcination and light irradiation on the structure and catalytic performance of the catalysts were compared. The active species of Au / α-Fe2O3 catalysts were also investigated. The results show that Au3 +, Au0 and Auδ + (0 <δ <1) exist simultaneously on the surface of Au / α-Fe2O3 catalyst treated at 110 ℃. The order of their activity for CO oxidation is Au3 +> Auδ +> Au0. The catalyst Au3 + has high content of Au3 + and high catalytic activity. The calcination at high temperature reduced the specific surface area of the catalyst and decreased the catalytic activity. The UV irradiation led to the gradual reduction of Au3 + Au0 particles growth, its catalytic deactivation is weaker than high temperature roasting.