Photocatalytic CO2 reduction with high turnover frequency and selectivity of formic acid formation using Ru(II) multinuclear complexes
Photocatalytic CO2 reduction with high turnover frequency and selectivity of formic acid formation using Ru(II) multinuclear complexes
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DOI：
10.1073/pnas.1118336109
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发表时间：
2012-09-25
影响因子：
11.1
通讯作者：
Ishitani, Osamu
中科院分区：
文献类型：
--
作者：
Tamaki, Yusuke;Morimoto, Tatsuki;Ishitani, Osamu
合成了两种不同比例的Ru(II)配合物--光敏剂和催化剂--的超分子。在二甲基甲酰胺-三乙醇胺混合溶液中，这些配合物可以利用多种波长的可见光和NADH模型化合物作为电子供体，以高选择性和持久性的光催化CO2还原甲酸。光敏剂单元与催化剂单元的比例越高，甲酸的产率越高。特别是，在已报道的光催化剂中，具有两个光敏剂单元和一个催化单元的三核配合物对CO_2的光催化还原(PHi(甲酸)=0.061，TONHCOOH=671)反应速度最快(TOFHCOOH=11.6min(-1))。另一方面，含有两种模型单核Ru(II)配合物和催化剂单元比较高的超分子的混合体系的光催化效率较低，并且在光催化反应过程中生成黑色的齐聚物和聚合物，从而降低了甲酸的产率。使用这里描述的超分子的甲酸的光催化形成通过两个顺序的过程进行：光敏剂单元被NADH模型化合物的光化学还原和分子内电子转移到催化剂单元。
Previously undescribed supramolecules constructed with various ratios of two kinds of Ru(II) complexes-a photosensitizer and a catalyst-were synthesized. These complexes can photocatalyze the reduction of CO2 to formic acid with high selectivity and durability using a wide range of wavelengths of visible light and NADH model compounds as electron donors in a mixed solution of dimethylformamide-triethanolamine. Using a higher ratio of the photosensitizer unit to the catalyst unit led to a higher yield of formic acid. In particular, of the reported photocatalysts, a trinuclear complex with two photosensitizer units and one catalyst unit photocatalyzed CO2 reduction (Phi(HCOOH) = 0.061, TONHCOOH = 671) with the fastest reaction rate (TOFHCOOH = 11.6 min(-1)). On the other hand, photocatalyses of a mixed system containing two kinds of model mononuclear Ru(II) complexes, and supramolecules with a higher ratio of the catalyst unit were much less efficient, and black oligomers and polymers were produced from the Ru complexes during photocatalytic reactions, which reduced the yield of formic acid. The photocatalytic formation of formic acid using the supramolecules described herein proceeds via two sequential processes: the photochemical reduction of the photosensitizer unit by NADH model compounds and intramolecular electron transfer to the catalyst unit.