Covalent triazine frameworks (CTFs) are normally synthesized by ionothermal methods. The harsh synthetic conditions and associated limited structural diversity do not benefit for further development and practical large‐scale synthesis of CTFs. Herein we report a new strategy to construct CTFs (CTF‐HUSTs) via a polycondensation approach, which allows the synthesis of CTFs under mild conditions from a wide array of building blocks. Interestingly, these CTFs display a layered structure. The CTFs synthesized were also readily scaled up to gram quantities. The CTFs are potential candidates for separations, photocatalysis and for energy storage applications. In particular, CTF‐HUSTs are found to be promising photocatalysts for sacrificial photocatalytic hydrogen evolution with a maximum rate of 2647 μmol h−1 g−1 under visible light. We also applied a pyrolyzed form of CTF‐HUST‐4 as an anode material in a sodium‐ion battery achieving an excellent discharge capacity of 467 mAh g−1.

Methods to synthesize crystalline covalent triazine frameworks (CTFs) are limited and little attention has been paid to development of hydrophilic CTFs and photocatalytic overall water splitting. A route to synthesize crystalline and hydrophilic CTF‐HUST‐A1 with a benzylamine‐functionalized monomer is presented. The base reagent used plays an important role in the enhancement of crystallinity and hydrophilicity. CTF‐HUST‐A1 exhibits good crystallinity, excellent hydrophilicity, and excellent photocatalytic activity in sacrificial photocatalytic hydrogen evolution (hydrogen evolution rate up to 9200 μmol g−1 h−1). Photocatalytic overall water splitting is achieved by depositing dual co‐catalysts in CTF‐HUST‐A1, with H2 evolution and O2 evolution rates of 25.4 μmol g−1 h−1 and 12.9 μmol g−1 h−1 in pure water without using sacrificial agent.

The synthesis of highly crystalline covalent triazine frameworks (CTFs) with ultrastrong covalent bonds (aromatic CN) from the triazine linkage presents a great challenge to synthetic chemists. Herein, the synthesis of highly crystalline CTFs via directly controlling the monomer feeding rate is reported. By tuning the feeding rate of monomers, the crystallization process can be readily governed in a controlled manner in an open system. The sample of CTF‐HUST‐HC1 with abundant exposed {001} crystal facets has the better crystallinity and thus is selected to study the effect of high crystallinity on photoelectric properties. Owing to the better separation of photogenerated electron–hole pairs and charge transfer, the obtained highly ordered CTF‐HUST‐HC1 has superior performance in the photocatalytic removal of nitric oxide (NO) than its lesser crystalline counterparts and g‐C3N4.

Covalent triazine frameworks (CTFs) are a class of semiconductive porous materials, showing enormous potential in many applications, such as gas adsorption and storage, and heterogeneous catalysis. At present, most of the studies on CTFs are focused on the structural design, synthesis, and applications, whereas very little attention is paid to morphological study, probably due to the difficulty in the control of the morphology via the conventional synthetic methods. In this work, a general approach is reported to fabricate morphological controllable CTFs by virtue of a mild polycondensation reaction via template method. As a proof of concept, a new type of hollow-structured CTFs is developed for the first time. The shell thickness of the hollow CTFs can be conveniently tuned by varying the amount of the template. Notably, the morphologies can be transformed from sphere to bowl with the decrease of the shell thicknesses. The hollow morphology of CTFs can efficiently improve the photocatalytic hydrogen evolution performance, in which the hydrogen evolution rate can be boosted by about 4 times as compared to the bulk state. The present study not only shows an effective strategy to construct morphology controllable CTFs, but also demonstrates an effective way to enhance photocatalytic performance for CTFs.

It remains a great challenge to design and synthesize a porous material for CO2 capture and sensing simultaneously. Herein, strategy of “cage to frameworks” is demonstrated to synthesize fluorescent porous organic polymer (pTOC) by using tetraphenylethylene‐based oxacalixarene cage (TOC) as the monomer. The networked cages (pTOC) have improved porous properties, including Brunauer–Emmett–Teller surface area and CO2 capture compared with its monomer TOC, because the polymerization overcomes the window‐to‐arene packing modes of cages and turns on their pores. Moreover, pTOC displays prominent reversible fluorescence enhancement in the presence of CO2 in different dispersion systems and fluorescence recovery for CO2 release in the presence of NH3·H2O, and is thus very effective to detect and quantify the fractions of CO2 in a gaseous mixtures.