Tin-porphyrin sensitized TiO2 for the production of H2 under visible light
Tin-porphyrin sensitized TiO2 for the production of H2 under visible light
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DOI：
10.1039/c0ee00205d
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发表时间：
2010-01-01
影响因子：
32.5
通讯作者：
Choi, Wonyong
中科院分区：
文献类型：
--
作者：
Kim, Wooyul;Tachikawa, Takashi;Choi, Wonyong
在可见光照射下，在锡卟啉（SnP）敏化的TiO 2系统中，在较宽的pH值范围内（pH 3-11），虽然SnP几乎不吸附在TiO 2上，成功地产生氢气。在SnP/TiO 2体系中照射9 h后产生的H-2数对应于410的周转数。在550 +/- 10 nm的单色辐射下，H-2释放的表观光子效率估计为35%。氢的光化学产生是通过形成p-自由基阴离子（SnP中心点-）介导的，该阴离子随后将电子转移到TiO 2。通过瞬态吸收光谱监测光生SnP中心点，并且其寿命足够长以经受从溶液本体到TiO 2表面的缓慢扩散，这使得SnP在TiO 2上的吸附不需要用于制氢。这与常见的钌络合物敏化的TiO 2系统形成了明显的对比，在常见的钌络合物敏化的TiO 2系统中，基本上需要敏化剂络合物的吸附，并且氢的产生限于允许敏化剂在TiO 2上吸附的酸性条件。SnP的光催化活性主要来自于Q带（500-650 nm），而不是Soret带（420-430 nm），Soret带的吸收强度更高。
Hydrogen was successfully produced under visible light irradiation in a tin porphyrin (SnP)-sensitized TiO2 system in the wide pH range (pH 3-11) although SnP hardly adsorbs on TiO2. The number of H-2 produced in the SnP/TiO2 system after 9 h irradiation corresponds to the turnover number of 410. The apparent photonic efficiency for H-2 evolution was estimated to be 35% with the monochromatic radiation of 550 +/- 10 nm. The photochemical production of hydrogen is mediated through the formation of the p-radical anion (SnP center dot-) that subsequently transfers electron to TiO2. The photogenerated SnP center dot- was monitored by transient absorption spectroscopy and its lifetime is long enough to survive the slow diffusion from the solution bulk to the TiO2 surface, which makes the adsorption of SnP on TiO2 not required for hydrogen production. This is clearly contrasted with the common ruthenium complex-sensitized TiO2 system where the adsorption of the sensitizer complex is essentially required and the hydrogen production is limited to the acidic condition where the adsorption of the sensitizers on TiO2 is allowed. The photocatalytic activity of SnP was mainly attributed to the Q-band (500-650 nm), not to the Soret band (420-430 nm) of which absorption intensity is much higher.