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采用广义梯度近似(GGA)密度泛函理论(DFT)的PW91方法结合周期性模型,在DNP基组下,利用Dmol3模块研究了CO和H2在真空和液体石蜡环境下在Cu(111)表面上不同位置的吸附.计算结果表明,溶剂化效应对H2和CO的吸附结构参数和吸附能的影响非常显著.在液体石蜡环境下,H2平行吸附在Cu(111)表面是解离吸附,而CO和H2在两种环境下的垂直吸附都是非解离吸附.相比真空环境吸附,在液体石蜡环境中,Cu(111)吸附CO时,溶剂化效应能够提高CO吸附的稳定性,同时有利于CO的活化.在真空中,H2只能以垂直方式或接近垂直方式吸附在Cu(111)表面.当Cu(111)顶位垂直吸附H2,相比真空环境吸附,溶剂化效应能够提高H2吸附的稳定性,但对H2的活化没有明显影响.Cu(111)表面的桥位或三重穴位(hcp和fcc)垂直吸附H2时,溶剂化效应能明显提高H2的活化程度,但降低H2的吸附稳定性;在液体石蜡中,当H2平行Cu(111)表面吸附时,溶剂化效应使H-H键断裂,一个H原子吸附在fcc位,另一个吸附在hcp位.
Using the PW91 method of generalized gradient approximation (GFT) coupled with the periodic model, CO and H2 were studied on the surface of Cu (111) under vacuum and liquid paraffin using the Dmol3 module under the DNP basis set The results show that the solvation effect is very significant on the adsorption parameters and adsorption energy of H2 and CO. In the liquid paraffin environment, H2 parallel adsorption is dissociative adsorption on the surface of Cu (111) And H2 in both environments are non-dissociative adsorption.Compared with the vacuum environment adsorption, the solvation effect of Cu (111) adsorbing CO can improve the stability of CO adsorption in the liquid paraffin environment, CO can be adsorbed on the surface of Cu (111) in a vertical or near vertical manner when H2 is adsorbed on the surface of Cu (111) , But had no obvious effect on the activation of H2.The solvation effect of H2 on the Cu (111) surface or the triple acupoints (hcp and fcc) adsorbed H2 vertically, but decreased the H2 adsorption Stability; In liquid paraffin, H2 adsorbed on the parallel Cu (111) surface , The solvent effect that the H-H bond is broken, a H atom position fcc adsorption, another adsorber in the hcp position.