Abstract:
Covalent triazine frameworks (CTFs) are a class of porous organic polymers that continuously attract growing interest because of their outstanding chemical and physical properties. However, the control of extended porous organic framework structures at the molecular scale for a precise adjustment of their properties has hardly been achieved so far. Here, we present a series of bipyridine-based CTFs synthesized through polycondensation, in which the sequence of specific building blocks is well controlled. The reported synthetic strategy allows us to tailor the physicochemical features of the CTF materials, including the nitrogen content, the apparent specific surface area, and optoelectronic properties. Based on a comprehensive analytical investigation, we demonstrate a direct correlation of the CTF bipyridine content with the material features such as the specific surface area, band gap, charge separation, and surface wettability with water. The entirety of these parameters dictates the catalytic activity as demonstrated for the photocatalytic hydrogen evolution reaction (HER). The material with the optimal balance between optoelectronic properties and highest hydrophilicity enables HER production rates of up to 7.2 mmol/(h·g) under visible light irradiation and in the presence of a platinum cocatalyst.
摘要:
共价三嗪骨架(CTFs)是一类多孔有机聚合物,由于其出色的化学和物理性质而不断吸引越来越多的兴趣。然而,迄今为止,在分子尺度上控制扩展的多孔有机骨架结构以精确调节其性能几乎没有实现。这里,我们提出了一系列通过缩聚合成的基于联吡啶的CTF,其中特定构建块的顺序得到了很好的控制。报道的合成策略使我们能够定制CTF材料的物理化学特征,包括氮含量,表观比表面积,和光电特性。基于全面的分析调查,我们证明了CTF联吡啶含量与比表面积等材料特征的直接相关性,带隙,电荷分离,和表面与水的润湿性。这些参数的全部决定了光催化析氢反应(HER)所证明的催化活性。在光电性能和最高亲水性之间具有最佳平衡的材料,在可见光照射和铂助催化剂存在下,HER的生产率高达7.2mmol/(h·g)。