Studies on the Protein- Chlorophyll Artificial Complexes Bearing Hydrogen-Evolving Function

本工作研究了水不溶性叶绿素a(CHLA)或钴(II)四苯基卟啉(CoTPP)以及甲基紫精、铂胶体催化剂和乙二胺四乙酸体系的光诱导产氢反应。用圆二色谱、吸收光谱、傅里叶变换红外光谱、稳态荧光光谱和荧光寿命测量等光谱方法，研究了不含甲基紫精和不含甲基紫精的情况下，氯丙交联剂和共聚TPP均溶于聚(L-谷氨酸)-表面活性剂体系.光谱研究表明，氯丙交联剂和共聚TPP被引入到聚(L-谷氨酸)-表面活性剂络合物中，并伴随着从无规卷曲构象向α-螺旋构象的转变.Chla或CoTPP与甲基紫精之间也发生了构象依赖性的电子转移。在可见光照射下，Chla和CoTPP的放氢速率都比没有络合物时显著增加。我们还观察到了二氧化钛(一种典型的半导体光催化剂)和石墨-二氧化硅(天然矿物之一)或单壁碳纳米管在水-醇混合物中产生氢气的强烈协同效应。在此基础上，我们对实际的制氢提出了挑战。

In this work, the photoinduced hydrogen production with systems containing water insoluble chlorophyll a (Chla) or Co(II)tetraphenylporphyrin (CoTPP), and also methylviologen, platinum colloidal catalyst and ethylenediaminetetraacetic acid was investigated. Chla and CoTPP were dissolved in aqueous poly (L-glutamate) and decylammonium chloride (DeAC) surfactant solutions.The systems were characterized in the absence and presence of methylviologen using spectroscopic methods such as circular dichroism, absorption spectroscopy, Fourier-transformed infra-red spectroscopy, steady state fluorescence spectroscopy and fluorescence lifetime measurements.The spectroscopic studies indicate that Chla and CoTPP are incorporated into poly(L-glutamate)-surfactant complexes accompanying a conformation change from the random coil to the α-helix of poly(L-glutamate). A conformation- dependent electron transfer also occurs between Chla or CoTPP and methylviologen.A drastic increase in the evolution rate of hydrogen occurred for both photocatalysts (Chla and CoTPP) under the visible-light irradiation in the presence of the poly (L-glutamate)-DeAC complex than in the absence of the complex.We also observed the drastic synergy effect of titanium oxide (a typical semiconductor photocatalyst) and graphite silica (one of natural minerals) or single-walled carbon nanotube for the production of hydrogen gas in water-alcohol mixtures.We are now challenging to the practical hydrogen production on the basis of the present results.