Rational design of carbon nitride photocatalysts by identification of cyanamide defects as catalytically relevant sites.
Rational design of carbon nitride photocatalysts by identification of cyanamide defects as catalytically relevant sites.
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DOI：
10.1038/ncomms12165
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发表时间：
2016-07-08
影响因子：
16.6
通讯作者：
Lotsch BV
中科院分区：
文献类型：
--
作者：
Lau VW;Moudrakovski I;Botari T;Weinberger S;Mesch MB;Duppel V;Senker J;Blum V;Lotsch BV
基于七嗪的聚合物瓜（也称为石墨碳氮化物，g-C3 N4）是一种很有前途的析氢光催化剂。尽管如此，试图改善其固有的低活性很少是基于合理的方法，因为缺乏基本的理解，其机械操作。在这里，我们采用分子heptazine为基础的模型催化剂，以确定作为光催化相关的“缺陷”的氰胺部分。我们利用这一知识来合理设计含有氨腈基团的氮化碳聚合物，与未改性的甜瓜相比，得到的材料的析氢速率和表观量子效率（400 nm）分别是其12倍和16倍。计算建模和材料表征表明，该部分改善了与铂助催化剂的配位（以及电荷转移动力学），并增强了光生载流子的分离。这里提出的合理的催化剂设计的知识转移证明提供了工程高性能庚嗪基光催化剂的概念框架。 石墨碳氮化物是一种很有前途的析氢光催化剂，尽管对其机理的理解有限。在这里，作者采用分子heptazine为基础的模型催化剂，以确定催化相关的缺陷，并合理地设计一个高活性的氮化碳光催化剂。
The heptazine-based polymer melon (also known as graphitic carbon nitride, g-C3N4) is a promising photocatalyst for hydrogen evolution. Nonetheless, attempts to improve its inherently low activity are rarely based on rational approaches because of a lack of fundamental understanding of its mechanistic operation. Here we employ molecular heptazine-based model catalysts to identify the cyanamide moiety as a photocatalytically relevant ‘defect'. We exploit this knowledge for the rational design of a carbon nitride polymer populated with cyanamide groups, yielding a material with 12 and 16 times the hydrogen evolution rate and apparent quantum efficiency (400 nm), respectively, compared with the unmodified melon. Computational modelling and material characterization suggest that this moiety improves coordination (and, in turn, charge transfer kinetics) to the platinum co-catalyst and enhances the separation of the photogenerated charge carriers. The demonstrated knowledge transfer for rational catalyst design presented here provides the conceptual framework for engineering high-performance heptazine-based photocatalysts. Graphitic carbon nitride is a promising hydrogen evolution photocatalyst, although there is limited understanding of its mechanistic operation. Here, the authors employ molecular heptazine-based model catalysts to identify catalytically relevant defects and to rationally design a highly active carbon nitride photocatalyst.