Exceptional Cocatalyst-Free Photo-Enhanced Piezocatalytic Hydrogen Evolution of Carbon Nitride Nanosheets from Strong In-Plane Polarization
Exceptional Cocatalyst-Free Photo-Enhanced Piezocatalytic Hydrogen Evolution of Carbon Nitride Nanosheets from Strong In-Plane Polarization
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DOI：
10.1002/adma.202101751
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发表时间：
2021-05-08
影响因子：
29.4
通讯作者：
Huang, Hongwei
中科院分区：
文献类型：
--
作者：
Hu, Cheng;Chen, Fang;Huang, Hongwei
利用机械能生产氢气正在成为一种有前景的可再生能源生产方式，但面临效率低和认知不足的挑战。在这项工作中，具有原子薄片状结构的石墨氮化碳（g-C3N4）被应用于显着的压电催化和光增强压电催化H-2生产。研究表明，g-C3N4中的反常压电性源于沿a轴的强面内极化，这是由叠加的极性三均三嗪单元和三角腔结构产生的挠曲电效应所贡献的，这为水还原反应提供了强大的电化学驱动力。此外，光增强的电荷转移使 g-C3N4 纳米片能够保留更多的极化电荷，以充分参与由应变诱导的碳空位富集的表面反应位点的反应。在没有任何助催化剂的情况下，g-C3N4纳米片可实现12.16 mmol g(-1) h(-1)的优异光压电催化H-2释放速率，远远超过先前报道的压电催化剂和g-C3N4光催化剂。此外，还公开了通过光压电催化生产增值氧化产物H2O2的高纯水分解性能。这项工作不仅揭示了g-C3N4作为压电半导体催化H-2析出的潜力，而且为光介导压电催化反应太阳能和机械能的转换开辟了新天地。
Utilizing mechanical energy to produce hydrogen is emerging as a promising way to generate renewable energy, but is challenged by low efficiency and scanty cognition. In this work, graphitic carbon nitride (g-C3N4) with an atomically thin sheet-like structure is applied for prominent piezocatalytic and photo-enhanced piezocatalytic H-2 production. It is revealed that the anomalous piezoelectricity in g-C3N4 originates from the strong in-plane polarization along the a-axis, contributed by the superimposed polar tri-s-triazine units and flexoelectric effect derived from the structured triangular cavities, which provides powerful electrochemical driving force for the water reduction reaction. Furthermore, the photo-enhanced charge transfer enables g-C3N4 nanosheets to reserve more energized polarization charges to fully participate in the reaction at the surface reactive sites enriched by strain-induced carbon vacancies. Without any cocatalysts, an exceptional photo-piezocatalytic H-2 evolution rate of 12.16 mmol g(-1) h(-1) is delivered by the g-C3N4 nanosheets, far exceeding that of previously reported piezocatalysts and g-C3N4 photocatalysts. Further, high pure-water-splitting performance with production of the value-added oxidation product H2O2 via photo-piezocatalysis is also disclosed. This work not only exposes the potential of g-C3N4 as a piezo-semiconductor for catalytic H-2 evolution, but also breaks a new ground for the conversion of solar and mechanical energy by photomediated piezocatalytic reaction.