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基于PCET的连接物限制电荷与Ir (III) 光反氧催化剂的重组

Hannah Sayre¹, Hunter H Ripberger¹, Emmanuel Odella²

¹Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.

Journal of the American Chemical Society

|August 11, 2021

概括

这项研究引入了一种由光系统II启发的新型光催化剂,利用分子内质子合电子转移 (PCET) 来显著减少电荷重组. 这种增强提高了光氧催化反应的效率.

科学领域:

摄影化学
催化剂
有机化学

背景情况:

电荷重组是光反应的一个关键限制,减少了量子产量.
在像光系统II这样的自然系统中观察到的质子合电子转移 (PCET) 机制提供了减轻这种情况的潜在策略.
复合物被广泛用作光催化剂,但它们的效率可能会受到快速电荷重组的阻碍.

研究的目的:

设计和合成一种新型的光催化剂,其中包含胺- (BIP) 部分.
研究分子内PCET对激发光催化剂中的电荷重组速率的影响.
评估减少电荷重组对模型光反应效率的影响.

主要方法:

胺- (BIP) 单元与复合体的2,2-二基连接体的共价连接 ([Ir(dF(CF3) ppy) 2 ((bpy) [PF6]).
修饰的复合物的光激发可诱导分子内PCET并形成电荷分离状态.
分析电荷分离状态和电子转移动态的光谱和电化学研究.
使用改性催化剂,用甲基基 (MV2+) 作为基质替代物的光催化降解.

主要成果:

修改后的光催化剂 ([Ir(dF(CF3)ppy) 2 ((BIP-bpy) [PF6]) 在光激发后成功地经历了分子内PCET.
BIP部分的存在使电荷重组率大约减慢了24倍.
这种降低电荷重组导致胺降低的量子效率增加了两倍以上.

结论:

灵感来自自然系统的内分子PCET是一种有效的策略,可以抑制光催化剂中的电荷重组.
设计的BIP功能化复合体在光电还原催化中表现出由于电荷分离的改善而提高的性能.
这种方法为开发各种有机转化效率更高的光催化剂提供了有希望的途径.

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