Efficient and Limiting Reactions in Aqueous Light-Induced Hydrogen Evolution Systems using Molecular Catalysts and Quantum Dots
Efficient and Limiting Reactions in Aqueous Light-Induced Hydrogen Evolution Systems using Molecular Catalysts and Quantum Dots
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DOI：
10.1021/ja501489h
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发表时间：
2014-05-28
影响因子：
15
通讯作者：
Llobet, Antoni
中科院分区：
文献类型：
--
作者：
Gimbert-Surinach, Carolina;Albero, Josep;Llobet, Antoni
由水和太阳能产生的氢对于减少对化石燃料的依赖具有很大的希望。最近已经证明，使用量子点作为光收集器与催化剂组合是获得光生氢的有价值的策略。然而，据报道，这些系统的光到氢的转化效率低于40%。低的转换效率主要是由于在不同的界面电荷转移反应发生在多组分系统在照明过程中的损失。在这项工作中，我们分析了所有涉及的反应在析氢催化的模型系统组成的CdTe量子点，分子钴催化剂和维生素C作为牺牲电子供体。结果表明，从量子点到催化剂的电子转移发生得足够快和有效（纳秒时间尺度），而反向电子转移和催化慢得多（毫秒和微秒时间尺度）。光驱动质子还原的进一步改进应该集中在催化速率的提高上，这应该至少在数百纳秒的时间尺度上。
Hydrogen produced from water and solar energy holds much promise for decreasing the fossil fuel dependence. It has recently been proven that the use of quantum dots as light harvesters in combination with catalysts is a valuable strategy to obtain photogenerated hydrogen. However, the light to hydrogen conversion efficiency of these systems is reported to be lower than 40%. The low conversion efficiency is mainly due to losses occurring at the different interfacial charge-transfer reactions taking place in the multicomponent system during illumination. In this work we have analyzed all the involved reactions in the hydrogen evolution catalysis of a model system composed of CdTe quantum dots, a molecular cobalt catalyst and vitamin C as sacrificial electron donor. The results demonstrate that the electron transfer from the quantum dots to the catalyst occurs fast enough and efficiently (nanosecond time scale), while the back electron transfer and catalysis are much slower (millisecond and microsecond time scales). Further improvements of the photodriven proton reduction should focus on the catalytic rate enhancement, which should be at least in the hundreds of nanoseconds time scale.