Carbon Nitride Photocatalysts for Water Splitting: A Computational Perspective
Carbon Nitride Photocatalysts for Water Splitting: A Computational Perspective
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DOI：
10.1021/jp507372n
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发表时间：
2014-10-30
影响因子：
3.7
通讯作者：
Zwijnenburg, Martijn A.
中科院分区：
文献类型：
--
作者：
Butchosa, Cristina;Guiglion, Pierre;Zwijnenburg, Martijn A.
我们研究了氮化碳材料作为水分解光催化剂的热力学能力，使用了一种计算方法，包括密度泛函理论（DFT）和时间依赖的DFT （TD-DFT）计算在三嗪基和七嗪基结构的簇模型上的结合。我们首先利用TD-DFT计算了不同簇模型的吸收光谱，并将这些光谱与实验测量的光谱进行了比较，然后利用DFT和TD-DFT计算了这些模型中自由电子、自由空穴和激子的还原势。我们预测，考虑的所有类别的氮化碳结构在热力学上应该能够还原质子和氧化水。我们进一步为纯氮化碳在实验中缺乏整体水分解活性的假设提供了证据，这是因为水氧化是一个四空穴反应，因此非常容易与电子空穴复合竞争。最后，我们提出，最近报道的负载聚吡咯纳米颗粒的氮化碳的总体水分解活性源于两种材料界面形成的结，这有助于保持电子和空穴分开。
We study the thermodynamic ability of carbon nitride materials to act as water splitting photocatalysts using a computational approach that involves a combination of density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations on cluster models of both triazine- and heptazine-based structures. We first use TD-DFT to calculate the absorption spectra of the different cluster models and compare these spectra to those measured experimentally and then calculate using DFT and TD-DFT the reduction potentials of the free electron, free hole, and exciton in these models. We predict that all classes of carbon nitride structures considered should thermodynamically be able to reduce protons and oxidize water. We further provide evidence for the hypothesis that the experimental lack of overall water splitting activity for pure carbon nitride arises from the fact that water oxidation is a four-hole reaction and hence very susceptible to competition with electronhole recombination. Finally, we propose that the recently reported overall water splitting activity of carbon nitride loaded with polypyrrole nanoparticles arises from a junction formed at the interface of both materials, which assists in keeping electrons and holes apart.