巴豆醛在Au(111)面上的吸附及选择性加氢机理研究

采用密度泛函理论计算了巴豆醛4种构型的稳定性,并选取最优构型进一步研究了其Au(111)面上的吸附及选择性加氢机理.计算结果表明,具有E-(s)-trans构型的巴豆醛稳定性最高.当巴豆醛通过C O吸附于Au(111)面的顶位时,该构型吸附能最大,吸附模型最稳定;巴豆醛向Au(111)表面转移电子0.045e,且其p轨道与金属表面的d轨道发生较强相互作用,使得巴豆醛的键级减弱.此外,通过分析各基元反应的活化能、反应热以及构型变化可知,巴豆醛在Au(111)面上按照2,1-加成机理(部分加氢机理)生成巴豆醇的可能性最大,且降低温度有利于反应转化率的提高.

Adsorption and Selective Hydrogenation Mechanism of Crotonaldehyde on Au(111) Surface

The stabilities of four possible configurations for crotonaldehyde were investigated with density functional theory( DFT) model. The most favorable configuration of crotonaldehyde was selected to explore the adsorption and its selective hydrogenation mechanism on the Au ( 111 ) surface was also investigated. The calculated results showed that the E-( s )-trans-crotonaldehyde was the most stable configuration. The adsorption at the top site was most stable when the crotonaldehyde on the Au(111) surface with C O. And its adsorption energy was maximum. The d orbitals of the metal surface interact strongly with the p orbitals of the crotonaldehyde. And the crotonaldehyde losed 0. 045 electrons after adsorption on the Au(111) surface. In addition, comparing the reaction energy, activation energy and structure change of each elementary steps, we obtained that the crotonaldehyde was more likely to follow the 2,1-addition mechanism(partial hydrogena-tion mechanism) to produce crotyl alcohol, and the lower temperature was helpful for the reaction to improve the conversion rate.