Exploring effects of intermittent light upon visible light promoted water oxidations
Exploring effects of intermittent light upon visible light promoted water oxidations
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DOI：
10.1039/c7se00304h
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发表时间：
2017-11
影响因子：
5.6
通讯作者：
D. Walsh;Pascaline Patureau;K. Robertson;S. Reeksting;Anneke T. Lubben;Salvador Eslava;M. Weller
中科院分区：
文献类型：
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作者：
D. Walsh;Pascaline Patureau;K. Robertson;S. Reeksting;Anneke T. Lubben;Salvador Eslava;M. Weller
可见光促进的光催化水氧化用于潜在的太阳能燃料生产已经被广泛研究，有许多关于试剂组分优化的报道。在这里，我们报告的日光等效光强度照明与调节短的黑暗时期的几秒钟的持续时间相比，标准的连续照明进行中的反应的影响的探索。与使用合成的低成本富含地球的氧化铁、钙锰氧化物和氧化钴纳米颗粒催化剂以及[Ru（bpy）3]2+捕光染料和电子受体的系统进行比较。在现场和真实的时间测量气态O2和质子生产的产量。该研究发现，低成本的催化剂可以通过使用简单的开/关照明来非常显著地增加O2产率、转换频率和改善反应曲线。测试了具有相同总光子通量的一系列定时，并确定了最佳定时。在光照条件下对光敏剂的影响的分析（通过质谱和紫外-可见光测量），连同与间歇反应相比的连续流系统的实施，都被用来帮助阐明观察到的反应产率的明显改善的机制。这些被认为源于过量氧化的敏化剂的自分解的减少以及在特定的光开：关定时下在金属氧化物表面处循环敏化剂氧化/还原与水氧化的更好同步。
Visible light promoted photocatalytic water oxidations for potential solar fuel production have been studied widely, with many reports on optimization of reagent components. Here we report an exploration on the effects upon ongoing reactions of daylight equivalent light intensity illumination with regulated short dark periods of a few seconds duration as compared to standard continuous illumination. Comparison was made with systems employing synthesized low cost earth abundant iron oxide, calciumoxomanganite and cobalt oxide nanoparticulate catalysts together with a [Ru(bpy)3]2+ light harvesting dye and an electron acceptor. Yields of gaseous O2 and proton production were measured in situ and in real time. The study found that low cost catalysts could give very significantly increased O2 yields, turn over frequency and improved reaction profiles by use of simple on/off illumination. A range of timings with identical overall photon flux were tested and an optimum determined. Analysis of effects upon the light sensitizer under the range of lighting conditions (through mass spectrometry and UV-vis measurements), together with implementation of a continuous flow system as comparison to the batch reactions, were all employed to help elucidate the mechanisms for the clear improvements in reaction yields observed. These are believed to stem from reduction in self-decomposition of excess oxidized sensitizer and better synchronization of cyclic sensitizer oxidation/reductions with water oxidation at the metal oxide surface at specific light on : off timing.