Enhancing the Ethynylation Performance of CuO-Bi2O3 Nanocatalysts by Tuning Cu-Bi Interactions and Phase Structures
Enhancing the Ethynylation Performance of CuO-Bi2O3 Nanocatalysts by Tuning Cu-Bi Interactions and Phase Structures
复制标题
通过调节 Cu-Bi 相互作用和相结构提高 CuO-Bi2O3 纳米催化剂的乙炔化性能
DOI：
10.3390/catal9010035
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发表时间：
2019-01-01
期刊：
影响因子：
3.9
通讯作者：
Jiang, Zheng
中科院分区：
文献类型：
--
作者：
Wang, Zhipeng;Niu, Zhuzhu;Jiang, Zheng
由氧化铜和氧化铋组成的催化体系通常用于乙基化工业生产1,4-丁炔二醇（BD）。然而，很少有研究探讨Bi对这些cu基催化剂的影响机理。本文采用共沉淀法，在不同温度下煅烧制备了一系列纳米CuO-Bi2O3催化剂。将所得催化剂应用于乙基化反应。催化剂的结构和晶体性质，它们的还原行为，以及铜和铋之间的相互作用，都强烈地依赖于温度。在600℃下煅烧时，CuO相中Cu和Bi之间的强相互作用促进了高度分散的活性Cu位点的形成，并稳定了Cu+价，从而获得了最高的BD产率。在700℃煅烧时，Bi2O3完全不存在，转化为尖晶石CuBi2O4相。经过8个催化循环，尖晶石Cu2+逐渐释放形成活性Cu+，不断补充金属Cu形成而导致的活性下降，提高了催化稳定性。此外，原位形成的表面Cu+离子与BD产率呈正相关，表明Cu+离子的数量是制备的CuO-Bi2O3催化剂上甲醛乙基化成BD的关键因素。基于这些结果和文献，我们提出了CuO-Bi2O3催化剂的乙基化反应机理，并为高效催化CuO-Bi2O3体系提供了一种简单的设计策略，该体系具有相当大的工业应用潜力。
Catalytic systems consisting of copper oxide and bismuth oxide are commonly employed for the industrial production of 1,4-butynediol (BD) through ethynylation. However, few studies have investigated the influence mechanism of Bi for these Cu-based catalysts. Herein, a series of nanostructured CuO-Bi2O3 catalysts were prepared by co-precipitation followed by calcination at different temperatures. The obtained catalysts were applied to the ethynylation reaction. The textural and crystal properties of the catalysts, their reduction behavior, and the interactions between copper and bismuth species, were found to strongly depend on temperature. When calcined at 600 °C, strong interactions between Cu and Bi in the CuO phase facilitated the formation of highly dispersed active cuprous sites and stabilized the Cu+ valency, resulting in the highest BD yield. Bi2O3 was completely absent when calcined at 700 °C, having been converted into the spinel CuBi2O4 phase. Spinel Cu2+ was released gradually to form active Cu+ species over eight catalytic cycles, which continuously replenished the decreasing activity resulting from the formation of metallic Cu and enhanced catalytic stability. Moreover, the positive correlation between the in-situ-formed surface Cu+ ions and BD yield suggests that the amount of Cu+ ions is the key factor for ethynylation of formaldehyde to BD on the as prepared CuO-Bi2O3 catalysts. Based on these results and the literature, we propose an ethynylation reaction mechanism for CuO-based catalysts and provide a simple design strategy for highly efficient catalytic CuO-Bi2O3 systems, which has considerable potential for industrial applications.