Branched polyethylenimine improves hydrogen photoproduction from a CdSe quantum dot/[FeFe]-hydrogenase mimic system in neutral aqueous solutions.
Branched polyethylenimine improves hydrogen photoproduction from a CdSe quantum dot/[FeFe]-hydrogenase mimic system in neutral aqueous solutions.
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DOI：
10.1002/chem.201406361
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发表时间：
2015-02
期刊：
影响因子：
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通讯作者：
Wenpeng Liang;Feng Wang;Min Wen;Jingxin Jian;Xu‐Zhe Wang;Bin Chen;C. Tung;Lizhu Wu
中科院分区：
文献类型：
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作者：
Wenpeng Liang;Feng Wang;Min Wen;Jingxin Jian;Xu‐Zhe Wang;Bin Chen;C. Tung;Lizhu Wu
大自然使用氢化酶在pH 7下催化质子还原，其超电势和催化效率可与铂电极相媲美。在过去的几年中，[FeFe]-氢化酶（[FeFe]-H2酶）模拟物已被证明是光驱动的H2释放的有效催化剂。然而，它仍然是一个重大的挑战，以实现H2生产由这样的人工光合系统在中性水溶液中。在这里，我们报告了一个新的系统，用于光催化析氢工作在一个广泛的pH值范围内，特别是在中性条件下。这种独特的体系由支化聚乙烯亚胺（PEI）接枝的[FeFe]-H2酶模拟物（PEI-g-Fe 2S 2）、MPA-CdSe量子点（MPA=巯基丙酸）和抗坏血酸（H2 A）在水中组成。由于PEI的次级配位球具有较高的缓冲能力和稳定能力，该体系在可见光照射下能够产生H2，基于PEI-g-Fe 2S 2中的Fe 2S 2活性位点，其转化数为10600。稳定性和活性比酸性或碱性条件下的相同系统好得多，并且据我们所知，它们是迄今为止已知的中性水溶液中从[FeFe]-H2酶模拟物光催化放氢的最高水平。
Nature uses hydrogenase enzyme to catalyze proton reduction at pH 7 with overpotentials and catalytic efficiencies that rival platinum electrodes. Over the past several years, [FeFe]-hydrogenase ([FeFe]-H2 ase) mimics have been demonstrated to be effective catalysts for light-driven H2 evolution. However, it remains a significant challenge to realize H2 production by such an artificial photosynthetic system in neutral aqueous solution. Herein, we report a new system for photocatalytic H2 evolution working in a broad pH range, especially under neutral conditions. This unique system is consisted of branched polyethylenimine (PEI)-grafted [FeFe]-H2 ase mimic (PEI-g-Fe2 S2 ), MPA-CdSe quantum dots (MPA=mercaptopropionic acid), and ascorbic acid (H2 A) in water. Due to the secondary coordination sphere of PEI, which has high buffering capacity and stabilizing ability, the system is able to produce H2 under visible-light irradiation with turnover number of 10 600 based on the Fe2 S2 active site in PEI-g-Fe2 S2 . The stability and activity are much better than that of the same system under acidic or basic conditions and they are, to the best of our knowledge, the highest known to date for photocatalytic H2 evolution from a [FeFe]-H2 ase mimic in neutral aqueous solution.