西湖大学徐宇曦团队报道了具有超高光催化性能的原子薄结晶二维三嗪聚合物的绿色和可扩展合成。相关研究成果于2023年5月12日发表于国际一流学术期刊《美国化学会杂志》。

具有适当带隙和单层厚度的结晶二维（2D）聚合物的可扩展和环保合成对于2D聚合物的基础研究和实际应用是非常期望的；然而，这仍然是一个相当大且尚未解决的挑战。

该文中，研究人员报道了一种方便而稳健的方法，通过一种新的无溶剂盐催化腈环三聚工艺合成了一系列厚度为～80nm的结晶共价三嗪框架纳米片（CTF-NSs），这使得能够在百克水平上大规模制备具有成本效益的结晶CTF-NSs。理论计算和详细实验首次表明，KCl等传统盐不仅可以像传统认为的那样作为物理模板，而且更重要的是，作为一种新型的绿色固体催化剂，可以有效地催化腈单体的环三聚反应，获得结晶的CTF-NSs。在简单的液相超声处理后，这些CTF NSs可以很容易地以高产率进一步剥离成大量的单层结晶2D三嗪聚合物（2D TPs）。

所获得的带隙为2.36 eV且富含三嗪活性基团的原子薄晶体2D TPs在可见光照射下表现出1321μmol h^–1的显著光催化析氢速率，在420 nm下的表观量子产率高达29.5%，并且具有优异的光催化整体水分解活性，其超过了所有的分子框架材料，并且是有史以来报道的最好的无金属光催化剂之一。此外，可加工的2D TPs可以很容易地组装在载体上作为光催化薄膜器件，这表明了优异的光催化性能（135.2 mmol h^–1 m^–2的析氢性能）。

附：英文原文

Title: Green and Scalable Synthesis of Atomic-Thin Crystalline Two-Dimensional Triazine Polymers with Ultrahigh Photocatalytic Properties

Author: Congxu Wang, Pengbo Lyu, Zhong Chen, Yuxi Xu

Issue&Volume: May 12, 2023

Abstract: Scalable and eco-friendly synthesis of crystalline two-dimensional (2D) polymers with proper band gap and single-layer thickness is highly desired for the fundamental research and practical applications of 2D polymers; however, it remains a considerable and unresolved challenge. Herein, we report a convenient and robust method to synthesize a series of crystalline covalent triazine framework nanosheets (CTF NSs) with a thickness of ～80 nm via a new solvent-free salt-catalyzed nitrile cyclotrimerization process, which enables the cost-effective large-scale preparation of crystalline CTF NSs at the hundred-gram level. Theoretical calculations and detailed experiments revealed for the first time that the conventional salts such as KCl can not only act as physical templates as traditionally believed but also more importantly can efficiently catalyze the cyclotrimerization reaction of carbonitrile monomers as a new kind of green solid catalysts to achieve crystalline CTF NSs. Upon simple liquid-phase sonication, these CTF NSs can be easily further exfoliated into abundant single-layer crystalline 2D triazine polymers (2D-TPs) in high yields. The obtained atomically thin crystalline 2D-TPs with a band gap of 2.36 eV and rich triazine active groups exhibited a remarkable photocatalytic hydrogen evolution rate of 1321 μmol h–1 under visible light irradiation with an apparent quantum yield up to 29.5% at 420 nm and excellent photocatalytic overall water splitting activity with a solar-to-hydrogen efficiency up to 0.35%, which exceed all molecular framework materials and are among the best metal-free photocatalysts ever reported. Moreover, the processable 2D-TPs could be readily assembled on a support as a photocatalytic film device, which demonstrated superior photocatalytic performance (135.2 mmol h–1 m–2 for hydrogen evolution).

DOI: 10.1021/jacs.3c02874

Source: https://pubs.acs.org/doi/10.1021/jacs.3c02874