Abstract:

A series of Cu₂O/TiO₂ catalysts were prepared by liquid reduction-deposition-precipitation technique from copper chloride as copper source, sodium hydroxide as precipitant, sodium L-ascrobate as reducer, and TiO₂ calcined at different temperatures as support. The catalysts were characterized by X-ray diffraction (XRD), H₂-temperature programmed reduction (H₂-TPR), nitrogen physisorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic activity of these catalysts were studied in formaldehyde ethynylation. The results showed that calcination temperature of TiO₂ support had great influence on the catalytic activity of Cu₂O/TiO₂. TiO₂ calcined at low temperature presented mainly as anatase phase and had weak interaction with Cu₂O, which could cause over reduction of active Cu₂O to inactive metal Cu and result in the decrease of catalytic activity. With the increase of calcination temperature, anatase TiO₂ gradually transformed to rutile TiO₂ which could inhibit over reduction of active Cu₂O due to its strong interaction with Cu₂O. As a result of efficient conversion of Cu₂O to active Cu (I) ethynlate, the Cu₂O/TiO₂ catalyst with TiO₂ support calcined at high temperatures had the best catalytic activity.

Key words: catalysis, support, Cu₂O/TiO₂, formaldehyde ethynylation, 1,4-butynediol

摘要：

以不同温度焙烧的TiO₂为载体，CuCl₂·2H₂O为铜源，NaOH为沉淀剂，L-抗坏血酸钠为还原剂，采用液相还原-沉积沉淀法制备了Cu₂O/TiO₂，借助X射线粉末衍射（XRD）、H₂程序升温还原（H₂-TPR）、N₂-物理吸附、透射电镜（TEM）、X射线光电子能谱（XPS）等手段，研究了TiO₂载体焙烧温度对Cu₂O/TiO₂甲醛乙炔化反应性能的影响。结果表明，低温焙烧得到的TiO₂载体以锐钛矿相存在，与Cu₂O物种间具有弱的相互作用，使得Cu₂O被过度还原为金属Cu，催化活性较低。随着载体焙烧温度的升高，TiO₂中出现金红石相，Cu₂O与载体间相互作用增强，Cu₂O高效转变为乙炔亚铜活性物种，使催化剂表现出最佳的催化性能。

关键词: 催化, 载体, Cu₂O/TiO₂, 甲醛乙炔化, 1,4-丁炔二醇