乙二醛和乙醛酸在Au(111),Pd(111)和Pt(111)面的吸附研究

Adsorption of Glyoxal and Glyoxylic Acid over Au(111),Pd(111) and Pt

采用第一性原理密度泛函理论,对乙二醛在Au(111),Pd(111),Pt(111)面的吸附进行系统研究.结果表明,乙二醛和乙醛酸在Au(111)表面的吸附最弱,在Pd(111)表面上的吸附能最高,生成的乙醛酸不易脱附,容易被进一步氧化生成草酸.Pt催化剂性能最佳,乙二醛强化学吸附在Pt(111)面,C-H键断裂,C-C键稳定,易被氧化成目标产物乙醛酸,同时,目标产物乙醛酸在Pt催化剂表面上易脱附,氧化程度小,选择性高,与实验结果吻合较好.

The adsorption of glyoxal on Au （111）,Pd （111） and Pt （111） was systematically studied by means of density functional calculations. The results showed that the adsorption of glyoxal and Glyoxylic acid on Au（111） is weak. On Pd （111） surface,the adsorption energy of glyoxal and Glyoxylic acid is the highest,in other words,the Glyoxylic acid is difficult to desorption and easily to further oxidation to form Oxalic acid. Whilst Pt was an excellent catalyst. Glyoxal was strongly chemical adsorbed on Pt （111）, the C-H bond was easier to break,and the C-C bond was stable. Glyoxal was easily to be oxidized into glyoxylic acid. Therefore, the degree of oxidation of glyoxylic acid was small, and the selectivity of glyoxylic acid was the best, which is consistent well with our experimental results.