Revealing and Facilitating the Rate-Determining Step for Efficient Sunlight-Driven Photocatalysis
Revealing and Facilitating the Rate-Determining Step for Efficient Sunlight-Driven Photocatalysis
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揭示并促进高效阳光驱动光催化的速率决定步骤
DOI：
10.1021/acs.jpclett.1c02101
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Chen Jiazang
中科院分区：
文献类型：
--
作者：
Xiang Houkui;Wang Zhijian;Chen Jiazang
由于表观活化能的复杂组成，即使在缓慢的析氧被有效的空穴提取取代后，光催化反应中的速率决定步骤如析氢仍在探索中。这个问题严重限制了某些策略的实施，如协同热效应。在这里，通过开发一种基于开路电位衰减的组合监测方法，我们证明了发生在decisecond到第二时间尺度上的光催化剂-助催化剂界面电子转移占主导地位的光催化析氢。这个时间尺度是大约6-12个数量级大于皮秒到微秒的广泛报道的值，并与Durrant等人预测的相媲美。为了提高光催化析氢，我们设法通过电子掺杂半导体表面来创建更多的中间站点。这一措施通过电荷复合促进了催化剂-助催化剂界面的电子转移，使协同热效应十分明显。
Because of the complex composition of the apparent activation energy, the rate-determining step in a photocatalytic reaction like hydrogen evolution is still being explored even after sluggish oxygen evolution is replaced with efficient hole extraction. This issue severely limits the implementation of certain strategies like the synergistic thermal effect. Here, by developing a combined monitor method based on open-circuit potential decay, we demonstrate that semiconductor–cocatalyst interfacial electron transfer occurring on a decisecond to second time scale dominates photocatalytic hydrogen evolution. This time scale is approximately 6–12 orders of magnitude larger than the widely reported values of picoseconds to microseconds and is comparable to that predicted by Durrant et al. To improve photocatalytic hydrogen evolution, we manage to create more intermediate sites by electronically doping the semiconductor surface. This measure promotes semiconductor–cocatalyst interfacial electron transfer by charge recombination and makes the synergistic thermal effect very evident.