Primary intermediates of oxygen photoevolution reaction on TiO2 (rutile) particles, revealed by in situ FTIR absorption and photoluminescence measurements
Primary intermediates of oxygen photoevolution reaction on TiO2 (rutile) particles, revealed by in situ FTIR absorption and photoluminescence measurements
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DOI：
10.1021/ja0388764
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发表时间：
2004-02-04
影响因子：
15
通讯作者：
Nakato, Y
中科院分区：
文献类型：
--
作者：
Nakamura, R;Nakato, Y
采用原位多次内反射红外（MIRIR）吸收和光致发光（PL）技术研究了TiO 2（金红石）/水溶液界面氧光氧化反应的主要中间产物。在溶液中存在10 mM Fe 3+的情况下，对TiO 2进行UV照射，导致在838 cm（-1）处出现新峰，在812 cm（-1）处出现肩峰。详细研究了溶液pH值、作为空穴清除剂的甲醇的存在以及水中的同位素交换（（H2O）-O-16-（H2O）-O-18）对光谱的影响，结果表明，838-和812-cm（-1）谱带可分别归属于表面TiOOH和TiOOTi的O-O伸缩模，它们是氧光析反应的主要中间产物。这些结果有力地支持了我们先前提出的机制，即光生氧是由H2O分子在表面晶格O位置上的光生空穴上的亲核攻击引发的，而不是由空穴氧化表面OH基团引发的。PL测量结果支持这一结论。提出了一个合理的反应方案，在pH值小于约12的水溶液中的TiO 2（金红石）上的光析氧。
Primary intermediates of oxygen photoevolution (water photooxidation) reaction at the TiO2 (rutile)/ aqueous solution interface were investigated by in situ multiple internal reflection infrared (MIRIR) absorption and photoluminescence (PL) measurements. UV irradiation of TiO2 in the presence of 10 mM Fe3+ in the solution caused the appearance of a new peak at 838 cm(-1) and a shoulder at 812 cm(-1). Detailed investigations of the effects of solution pH, the presence of methanol as a hole scavenger, and isotope exchange in water ((H2O)-O-16-(H2O)-O-18) on the spectra have shown that the 838- and 812-cm(-1) bands can be assigned to the O-O stretching mode of surface TiOOH and TiOOTi, respectively, produced as primary intermediates of the oxygen photoevolution reaction. The results give strong support to our previously proposed mechanism that the oxygen photoevolution is initiated by a nucleophilic attack of a H2O molecule on a photogenerated hole at a surface lattice O site, not by oxidation of surface OH group by the hole. The conclusion is supported by PL measurements. A plausible reaction scheme is proposed for the oxygen photoevolution on TiO2 (rutile) in aqueous solutions of pH less than about 12.