Cu对K-LaZrO_2异丁醇合成催化剂的影响

Influence of Cu on the K-LaZrO_2 Catalyst for Isobutanol Synthesis

采用X射线衍射(XRD)、程序升温脱附(TPD)、X射线光电子能谱(XPS)、傅里叶变换红外(FTIR)光谱技术及富集法考察了K-La Zr O2和K-Cu La Zr O2催化剂结构、CO和H2在锆基催化剂上的吸附行为及异丁醇合成活性的影响.结果表明,催化剂添加Cu后,与Zr形成较好的固溶体,促进了Cu O的分散,且抑制了Zr O2结晶,增强Cu-Zr相互作用,提高了催化活性.CO-TPD结果显示,引入Cu后,催化剂表面CO吸附量明显增加,有利于碳链增长;H2-TPD结果显示,与活性相关的低温脱附氢量也明显增加.另外,FTIR及富集法结果发现,Cu的引入促进了表面C1物种的形成,增加了表面C1物种含量,促进了碳链增长,明显改善了异丁醇的选择性.在p=10.0 MPa,空速(GHSV)=3000 h-1,T=360°C,V(H2)/V(CO)=1:1条件下,异丁醇选择性达到48.5%.

The K-LaZrO_2 and K-CuLaZrO_2 catalysts used for the synthesis of isobutanol from syngas have been characterized by X-ray diffraction （XRD）, temperature programmed desorption （TPD）, X-ray photoelectron spectrometry （XPS）, Fourier transform infrared （FTIR） spectroscopy, and chemical enrichment methods. The results of these analyses indicated that a solid solution of Cu-Zr was formed after the addition of Cu, and that the CuO was well dispersed. Furthermore, the addition of Cu inhibited the formation of t-ZrO2. CO-TPD showed that the addition of Cu led to an increase in the amount of CO adsorbed by the catalyst. Furthermore, H2-TPD showed that the addition of Cu led to an increase in the amount of H2 adsorbed at low temperatures, which was related to the activity of catalyst. The results of FTIR and chemical enrichment analyses also revealed that the level of CO adsorption increased following the addition of Cu, as well as amount of C1 intermediates. Taken together, these results indicated that the activity of catalyst was significantly enhanced by the addition of Cu and that the selectivity towards isobutanol increased up to 48.5% when the reaction was conducted at p=10.0 MPa, gas hourly space velocity （GHSV） = 3000 h^-1, T=360℃, and V（H2）/V（CO）=1：1.