A photoluminescent covalent triazine framework: CO₂ adsorption, light-driven hydrogen evolution and sensing of nitroaromatics

Abstract

A highly photoluminescent (PL) porous covalent triazine-based framework (PCTF-8) is synthesized from tetra(4-cyanophenyl) ethylene by using trifluoromethanesulfonic acid as the catalyst at room temperature. Due to triazine units in the framework, the PCTF-8 exhibits excellent thermal stability (>400 degrees C). The Brunauer-Emmett-Teller (BET) specific surface area of PCTF-8 is 625 m(2) g(-1) which is lower than the one obtained from the synthesis under Lewis acid conditions (ZnCl2). At 1 bar and 273 K, the PCTF-8 adsorbs a significant amount of CO2 (56 cm(3) g(-1)) and CH4 (17 cm(3) g(-1)) which is highly comparable to nanoporous 1,3,5-triazine frameworks (NOP-1-6, 29-56 cm(3) g(-1)). This nitrogen rich framework exhibits good ideal selectivity (61 : 1 (85% N-2 : 15% CO2) at 273 K, 1 bar). Thus, it can be used as a promising candidate for potential applications in post-combustion CO2 capture and sequestration technologies. In addition, photoluminescence properties as well as the sensing behaviour towards nitroaromatics have been demonstrated. The fluorescence emission intensity of PCTF-8 is quenched by ca. 71% in the presence of 2,4,6-trinitrophenol (TNP). From time-resolved studies, a static quenching behaviour was found. This high photoluminescence property is used for hydrogen evolving organic photocatalysis from water in the presence of a sacrificial electron donor and a cocatalyst

Covalent Triazine‐based Frameworks—Tailor‐made Catalysts and Catalyst Supports for Molecular and Nanoparticulate Species

“…Thus, the materials derived from the milder Brønsted acid approach might reflect the rather expected porosity of highly defined and theoretically ideal triazine frameworks. However, in some cases even for the Brønsted acid approach, pronounced carbonitrile bands around 2220 cm −1 in FT‐IR‐spectra indicate incomplete conversion of nitrile groups into triazine rings . Therefore, incomplete polymerization and structural defects cannot fully be excluded at this point.…”

Trends and challenges for microporous polymers

“…149 Following this work, several more CMPs have been suggested as interesting photocatalysts for hydrogen production, e.g. conjugated benzene and spirobifluorene, 150 benzodiazole 151 and triazine 152 -based networks. An illustrative example to which level the tailoring of organic photocatalysts can possibly proceed was recently shown in the preparation of CMPs in which certain tectons as chromophores were connected with metal coordinating linkers, namely bipyridine (Fig.…”

Perylene‐Containing Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution

“…Photocatalytic hydrogen evolution experiment was carried out by using these polymer networks as unprocessed powders. Triethanolamine was selected as sacrificial agent since it shows the highest photocatalytic activity in this system for the tested sacrificial agents (Figure a), as observed for most reported polymer photocatalytic systems . Steady hydrogen production was achieved with all of the as‐prepared PrCMPs from water containing 20 vol% triethanolamine under UV–visible light illumination (λ > 300 nm) even in the absence of noble metal catalysts such as Pt, as shown in Figure b.…”