论文部分内容阅读
催化剂表面的酸碱中心常常是反应发生的活性部位,其酸碱中心的种类、强度和数量的多少,直接影响催化剂的催化活性。拟利用分子模拟方法从电荷分析、Fukui函数及碱性探针吸附能等方面来计算铜催化剂的酸碱性,以求进一步理解铜催化剂的催化性能。本文从模拟方面分别揭示了Cu催化剂上的酸碱中心,研究结果表明;当有缺电子的分子或基团攻击时,纯铜表面具有亲核性,即有L碱中心;而当有富电子的分子或基团攻击时,纯铜表面具有亲电性,即有L酸中心。在乙醇脱氢过程中会产生很多游离态的H,铜可以接受质子,因而具有B碱中心;但不具备给出质子的能力,没有B酸中心。
The acid-base center of the catalyst surface is often the active site where the reaction takes place. The type, intensity and amount of the acid-base center directly affect the catalytic activity of the catalyst. It is proposed to calculate the acidity and alkalinity of copper catalysts from the aspects of charge analysis, Fukui function and the adsorption energy of basic probes using molecular simulation methods in order to further understand the catalytic performance of copper catalysts. In this paper, the acid-base centers of Cu catalysts are respectively revealed from the simulation results. The results show that when copper is attacked by an electron-deficient molecule or group, the surface of the pure copper is nucleophilic, that is, there is an L-base; Molecules or groups attacks, pure copper surface with electrophilic, that is, L acid center. During dehydrogenation of ethanol, many free H species are produced. Copper accepts protons and therefore has a B base center; however, it does not have the ability to give a proton without a B acid site.