Molecular co-catalyst accelerating hole transfer for enhanced photocatalytic H2 evolution.
Molecular co-catalyst accelerating hole transfer for enhanced photocatalytic H2 evolution.
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分子助催化剂加速空穴传输以增强光催化析氢
DOI：
10.1038/ncomms9647
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发表时间：
2015-10-21
影响因子：
16.6
通讯作者：
Xie Y
中科院分区：
文献类型：
--
作者：
Bi W;Li X;Zhang L;Jin T;Zhang L;Zhang Q;Luo Y;Wu C;Xie Y
在人工光催化中，空穴转移动力学的迟缓和由此产生的高电荷复合速率一直是光催化效率的致命弱点。在这里，我们展示了水溶性分子作为助催化剂来加速空穴转移，从而提高光催化析氢活性。三氟乙酸由于其可逆的氧化还原偶TFA·/TFA−而成为均相助催化剂，不仅使助催化剂与反应物之间的接触面积最大，而且极大地促进了空穴转移。因此，K4Nb6O17纳米片状催化剂在TFA存在的情况下，光催化产氢速率显著提高，是空白实验的32倍。分子助催化剂代表了一种新的、简单而高效的方法来抑制光生电荷的复合，并为建立高效的光合作用系统提供了肥沃的新土壤，避免了使用贵金属助催化剂。提高光催化表面空穴转移的动力学有助于提高整体效率，使其更接近实际可实现的水平。在这里，作者使用三氟乙酸来实现这一目标，并显著提高了K4Nb6O17的光催化析氢活性。
In artificial photocatalysis, sluggish kinetics of hole transfer and the resulting high-charge recombination rate have been the Achilles' heel of photocatalytic conversion efficiency. Here we demonstrate water-soluble molecules as co-catalysts to accelerate hole transfer for improved photocatalytic H2 evolution activity. Trifluoroacetic acid (TFA), by virtue of its reversible redox couple TFA·/TFA−, serves as a homogeneous co-catalyst that not only maximizes the contact areas between co-catalysts and reactants but also greatly promotes hole transfer. Thus K4Nb6O17 nanosheet catalysts achieve drastically increased photocatalytic H2 production rate in the presence of TFA, up to 32 times with respect to the blank experiment. The molecular co-catalyst represents a new, simple and highly effective approach to suppress recombination of photogenerated charges, and has provided fertile new ground for creating high-efficiency photosynthesis systems, avoiding use of noble-metal co-catalysts. Enhancing the kinetics of hole transfer at photocatalytic surfaces serves to promote the overall efficiency closer to practically implementable levels. Here, the authors employ trifluoroacetic acid to achieve this goal and significantly improve the photocatalytic H2 evolution activity of K4Nb6O17.