Adsorption and photocatalytic decomposition of amino acids in TiO2 photocatalytic systems.
Adsorption and photocatalytic decomposition of amino acids in TiO2 photocatalytic systems.
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DOI：
10.1021/jp065255z
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发表时间：
2006-11
期刊：
影响因子：
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通讯作者：
T. Tran;A. Nosaka;Y. Nosaka
中科院分区：
文献类型：
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作者：
T. Tran;A. Nosaka;Y. Nosaka
采用Zeta电位和1H NMR研究了7种氨基酸在TiO 2水悬浮液中的吸附和光解行为。对Phe、Trp、Asn、His和Ser，TiO 2的等电点（IEP）随着降解速率的增加而向较低的pH方向移动，表明这些氨基酸的有效吸附和光催化位点应该是固体表面的碱性末端OH。由于比其它氨基酸分解更快的氨基酸在其侧链中含有-OH（Ser）、-NH（Trp、His）或-NH 2（Asn），因此认为它们更优选通过侧链与碱性末端OH基团相互作用，并且容易受到光催化氧化。另一方面，Ala相互作用与酸性桥接的OH在TiO 2上引起IEP移位到更高的pH值。表面羟基基团与氨基酸的羧基的相关性通过使用煅烧TiO 2没有表面羟基基团进行验证。
The adsorption and photodecomposition of seven kinds of amino acids on a TiO2 surface were investigated by zeta potential measurements and 1H NMR spectroscopy in TiO2 aqueous suspension systems. The decomposition rates increased in the order of Phe < Ala < Asp < Trp < Asn < His < Ser. For Phe, Trp, Asn, His, and Ser, the isoelectric point (IEP) of TiO2 shifted to a lower pH with increasing decomposition rates upon adsorption on TiO2, suggesting that the effective adsorption and photocatalytic sites for these amino acids should be the basic terminal OH on the solid surface. Since the amino acids that decomposed faster than the others contain -OH (Ser), -NH (Trp, His), or -NH2 (Asn) in their side chain, they are considered to interact with the basic terminal OH groups more preferably by the side chain and are vulnerable to photocatalytic oxidation. On the other hand, Ala interacts with the acidic bridged OH on TiO2 to cause an IEP shift to a higher pH. The correlation of the surface hydroxyl groups with the photocatalysis of amino acids was verified by the use of calcined TiO2 without surface hydroxyl groups.