甘氨酸在TiO₂(110)单晶表面的扫描隧道显微镜研究

STM study of glycine on TiO2(110) single crystal surfaces.

作者信息

Qiu Tingzhu, Barteau Mark A

机构信息

Center for Catalytic Science and Technology, Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA.

出版信息

J Colloid Interface Sci. 2006 Nov 1;303(1):229-35. doi: 10.1016/j.jcis.2006.07.053. Epub 2006 Jul 26.

DOI:10.1016/j.jcis.2006.07.053

PMID:16919666

Abstract

The adsorption of glycine (NH2CH2COOH) was examined by scanning tunneling microscopy (STM) on TiO2(110) surfaces at room temperature. A (2x1) ordered overlayer was observed on the TiO2(110)-(1x1) surface. The adsorption of acetic acid and propanoic acid was also investigated on this surface and their STM images were quite similar to that of glycine. Since acetate and propanoate are formed by dissociative adsorption of these acids on TiO2(110), it is proposed that glycine adsorbs in the same way to form a glycinate. The amino group in the glycinate adlayer structurally analogous to those formed from aliphatic carboxylic acids would be extended away from the surface and potentially free to participate in additional reactions. The underlying structure of the TiO2 surface is important in determining the structure of the glycinate adlayer; no ordering of these adsorbates was observed on the TiO2(110)-(1x2) surface.

摘要

在室温下，通过扫描隧道显微镜（STM）研究了甘氨酸（NH2CH2COOH）在TiO2(110)表面的吸附情况。在TiO2(110)-(1x1)表面观察到一个(2x1)有序覆盖层。还研究了乙酸和丙酸在该表面的吸附情况，它们的STM图像与甘氨酸的非常相似。由于乙酸盐和丙酸盐是这些酸在TiO2(110)上解离吸附形成的，因此有人提出甘氨酸以相同方式吸附形成甘氨酸盐。甘氨酸盐吸附层中的氨基在结构上类似于由脂肪族羧酸形成的氨基，会从表面伸展出去，并有可能自由地参与其他反应。TiO2表面的底层结构对于确定甘氨酸盐吸附层的结构很重要；在TiO2(110)-(1x2)表面未观察到这些吸附质的有序排列。