Search Results (29)

Covalent triazine frameworks (CTFs) have gained recognition as stable porous organic polymers, for example, for CO₂ separation. From the monomer 4,4′-(phenazine-5,10-diyl)dibenzonitrile (pBN), new pBN-CTFs were synthesized using the ionothermal method with a variation in temperature (400 and 550 °C) and the ZnCl₂-to-monomer ratio (10 and 20). N₂ adsorption yielded BET surface areas up to 1460 m²g ⁻¹. The pBN-CTFs are promising CO₂ adsorbents and are comparable to other benchmark CTFs such as CTF-1 with a CO₂ uptake of pBN-CTF-10-550 at 293 K of up to 54 cm³ g⁻¹ or 96 mg g⁻¹, with a CO₂/CH₄ IAST selectivity of 22 for a 50% mixture of CO₂/CH₄. pBN-CTF-10-400 has a very high heat of adsorption of 79 kJ mol⁻¹ for CO₂ near zero coverage in comparison to other CTFs, and it also stays well above the liquefaction heat of CO₂ due to its high microporosity of 50% of the total pore volume. Full article

Hybrid materials based on porous organic polymers (POPs) and metal–organic frameworks (MOFs) are increasing attention for advanced separation processes due to the possibility to combine their properties. POPs provide high surface areas, chemical stability, and tunable porosity, while MOFs contribute a high variety of defined crystalline structures and enhanced separation characteristics. The combination (or hybridization) with PIMs gives rise to mixed-matrix membranes (MMMs) with improved permeability, selectivity, and long-term stability. However, interfacial compatibility remains a key limitation, often addressed through polymer functionalization or controlled dispersion of the MOF phase. MOF/COF hybrids are more used as biochemical sensors with elevated sensitivity, catalytic applications, and wastewater remediation. They are also very well known in the gas sorption and separation field, due to their tunable porosity and high electrical conductivity, which also makes them feasible for energy storage applications. Last but not less important, hybrids with other POPs, such as hyper-crosslinked polymers (HCPs), covalent triazine frameworks (CTFs), or conjugated microporous polymers (CMPs), offer enhanced functionality. MOF/HCP hybrids combine ease of synthesis and chemical robustness with tunable porosity. MOF/CTF hybrids provide superior thermal and chemical stability under harsh conditions, while MOF/CMP hybrids introduce π-conjugation for enhanced conductivity and photocatalytic activity. These and other findings confirm the potential of MOF-POP hybrids as next-generation materials for gas separation and carbon capture applications. Full article

Hydroformylation is one of the most widely applied homogeneous catalytic processes in the chemical industry, constituting the predominant manufacturing platform for aldehyde synthesis at commercial scales. Nevertheless, hydroformylation shares with traditional homogeneous catalysis the inherent limitation of difficult catalyst recovery and recycling. Developing heterogeneous catalysts for such reactions is thus critically needed. Herein, a stable nitrogen-rich covalent triazine framework (CTF) was synthesized via a mild Friedel–Crafts alkylation method and employed as a support for Rh single-atom catalysts (Rh/CTF-TPA). In the hydroformylation of 1-decene, the Rh/CTF-TPA catalyst exhibits an exceptional reaction efficiency (TOF > 1900 h⁻¹), outperforming the homogeneous Rh(CO)₂(acac). Experimental and characterization results revealed that the CTF support enhances catalytic performance through two key mechanisms: (1) strong enrichment of reactants within its special structure, and (2) efficient dispersion of Rh single-atom sites stabilized by abundant nitrogen coordination. This work demonstrates a rational design strategy for heterogeneous hydroformylation catalysts by leveraging nitrogen-rich porous frameworks to synergistically optimize metal anchoring and reactant enrichment, offering a promising alternative to conventional homogeneous systems. Full article

Covalent triazine frameworks (CTFs) are a class of porous organic semiconductors containing a large number of triazine units, which gives them many properties suitable for photocatalysis, such as high porosity, good tunability, and excellent chemical stability. However, it is difficult to achieve high activity, stability, and selectivity at the same time using a single CTF in a specific catalytic reaction. Therefore, it is necessary to find ways to combine CTFs with other materials to improve their photocatalysis activity. From this perspective, some construction methods and the latest progress of CTF-based composites are presented, and their applications in the field of photocatalysis are introduced. Finally, the future of CTF materials in catalytic applications is proposed, which provides some insights into the research and exploration of CTF-based composites. Full article

There are few examples of covalent organic frameworks (COFs) based on phosphorus as the building element, probably because the structure of most phosphorus derivatives is pyramidal, which may prevent the stacking expected for classical 2-dimensional COFs. In addition, they are generally associated with linear difunctional derivatives. In this paper is reported the original association of a trifunctional 3-D compound with a trifunctional 2-D compound in an attempt to get a new COF. The condensation reaction between a thiophosphate derivative bearing three aldehydes and the trihydrazinotriazine has been carried out with the aim of obtaining either a COF or simply a porous organic polymer (POP), consisting in both cases of associated macrocycles, affording a new covalent triazine framework (CTF). The material resulting from this condensation has been characterized by multinuclear MAS NMR (³¹P, ¹H, and ¹³C), IR, and thermogravimetric analysis (TGA). All these data confirmed the condensation reactions. However, BET (Brunauer–Emmett–Teller) measurements indicated that the porosity of this material is low. Trapping dyes in solution, as a model of pollutants, by the insoluble porous material 3 has been attempted. Full article

The utilization of covalent triazine frameworks (CTFs) as photocatalysts has witnessed rapid advancements in the field of photocatalysis. However, the presence of residual components in certain CTFs materials is widely ignored as regards their influence on photocatalytic performance. In this study, we find that trifluorosulfonic acid (TfOH) molecules stably exist in the amino-functionalized CTF-NH₂ framework, which enhance the affinity for water. The experimental results indicate that the residual TfOH elevates the VB position of CTF-NH₂, facilitating the oxidization of both water and sacrificial agents. Moreover, the present of TfOH accelerates the separation and transfer of photogenerated charge carriers to the Pt cocatalyst. Consequently, CTF-NH₂-F containing residual TfOH molecules demonstrates a significant enhancement in the photocatalytic hydrogen evolution, achieving about 250 µmol over a duration of 3 h of illumination, which represents a 2.5-fold increase compared to that observed for CTF-NH₂. This research underscores the substantial impact that residues exert on photocatalytic performance. Full article

Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) is a highly toxic organophosphorus insecticide, and its persistence in air, water, and soil poses potential threats to human health and ecosystems. Covalent triazine frameworks (CTFs), with their sufficient visible-light harvesting capacity, ameliorated charge separation, and exceptional redox ability, have emerged as promising candidates for the photocatalytic degradation of DDVP. Nevertheless, pure CTFs lack effective oxidative active sites, resulting in elevated reaction energy barriers during the photodegradation of DDVP. In this work, density functional theory (DFT) calculations were employed to investigate the impact of various oxygen-containing acid groups (-COOH, -HSO₃, -H₂PO₃) on DDVP photodegradation performance. First, simulations of the structure and optical properties of modified CTFs reveal that oxygen-containing acid groups induce surface distortion and result in a redshift in the absorption edge. Subsequently, analysis of the density of states, frontier molecular orbitals, surface electrostatic potential, work function, and dipole moment demonstrates that oxygen-containing acid groups enhance CTF polarization, facilitate charge separation, and ameliorate their oxidative capability. Additionally, the free-energy diagram of DDVP degradation uncovers that oxygen-containing acid groups lower the energy barrier by elevating the adsorption and activation capability of DDVP. Notably, -H₂PO₃ presents optimal potential for the photodegradation of DDVP by unique electronic structure and activation capability. This work offers a valuable reference for the development of oxygen-containing acid CTF-based photocatalysts applied in degrading toxic organophosphate pesticides. Full article

Triazine-based covalent organic framework CTF-1 was synthesized via polymerization of 1,4-dicyanobenzene in the presence of zinc chloride. Two different methods of the post-synthesis treatment of the obtained material were compared. It was demonstrated that ultrasonication effectively removes impurities from CTF-1. Adsorption of hydrocarbon gases (methane and ethane) and carbon dioxide was measured at 298 K in a wide pressure range for the first time. Ideal selectivity and IAST values for methane/ethane and methane/CO₂ pairs were calculated from the obtained isotherms. Full article

Covalent Organic Frameworks (COFs) demonstrate promising potential in the photocatalytic synthesis of H₂O₂ owing to favorable light absorption, superior charge separation, and considerable surface area. However, the efficiency of H₂O₂ photosynthesis is impeded by insufficient O₂ adsorption sites and a high reaction barrier. In this work, various metal single atoms (Fe, Co, Ni) are introduced onto covalent triazine frameworks (CTFs) with N-N coordination sites to significantly enhance O₂ adsorption and optimize H₂O₂ synthesis. Computational findings suggest that the presence of Fe, Co, and Ni not only enhances O₂ adsorption but also exerts an influence on the reaction pathway of H₂O₂. Significantly, Fe exhibits a distinct advantage in modulating O₂ adsorption through its unique electron spin state when compared to Co and Ni, as confirmed by crystal orbital Hamilton population (COHP) analysis. Additionally, this integration of metal atoms also improves light absorption and charge separation in CTFs. The study provides strategic insight into elevating H₂O₂ production by incorporating tailored metal single atoms into COFs. Full article

This study reports on a metal-free Covalent Triazine Framework (CTF) incorporating bithiophene structural units (TP-CTF) with a semicrystalline structure as an efficient heterogeneous photocatalyst under visible light irradiation. The physico-chemical properties and composition of this material was confirmed via different characterization solid-state techniques, such as XRD, TGA, CO₂ adsorption and FT-IR, NMR and UV-Vis spectroscopies. The compound was synthesized through a solvothermal process and was explored as a heterogeneous photocatalyst for the oxidative coupling of amines to imines under visible light irradiation. TP-CTF demonstrated outstanding photocatalytic activity, with high conversion rates and selectivity. Importantly, the material exhibited exceptional stability and recyclability, making it a strong candidate for sustainable and efficient imine synthesis. The low bandgap of TP-CTF enabled the efficient absorption of visible light, which is a notable advantage for visible-light-driven photocatalysis. Full article

Chiral porous organic frameworks have emerged in the last decade as candidates for heterogeneous asymmetric organocatalysis. This review aims to provide a summary of the synthetic strategies towards the design of chiral organic materials, the characterization techniques used to evaluate their chirality, and their applications in asymmetric organocatalysis. We briefly describe the types of porous organic frameworks, including crystalline (covalent organic frameworks, COFs) and amorphous (conjugated microporous polymers, CMPs; covalent triazine frameworks, CTFs and porous aromatic frameworks, PAFs) materials. Furthermore, the strategies reported to incorporate chirality in porous organic materials are presented. We finally focus on the applications of chiral porous organic frameworks in asymmetric organocatalytic reactions, summarizing and categorizing all the available literature in the field. Full article

A simple procedure of calcination under an Ar atmosphere has been successfully applied to create a covalent triazine framework bearing pyridine-type carbonitride moieties (PCN@CTF). The appending of PCN on the CTF led to visible light absorption at up to 600 nm in the UV/Vis diffuse-reflectance spectra. Photoluminescence and electrochemical impedance spectroscopy have been applied to clarify how modification of the CTF with PCN enhanced the separation efficiency of photoexcited charge carriers. An optimized 1%PCN@CTF sample showed the highest photocatalytic hydrogen evolution reaction (HER) rate of 170.2 ± 2.3 μmol g⁻¹·h⁻¹, 3.9 times faster than that over the pristine CTF. The apparent quantum efficiency of the HER peaked at (7.57 ± 0.10)% at 490 nm. This representative 1% PCN@CTF sample maintained continuous function for at least 15 h. This work provides new guidance for modification with PCN materials as a means of obtaining high photocatalytic efficiency and sheds light on the effect of appended pyridine rings on a CTF. Full article

Photocatalysis offers a sustainable approach for recalcitrant organic pollutants degradation, yet it is still challenging to seek robust photocatalysts for application purposes. Herein, a novel NiFe layered double hydroxide (LDH)/covalent triazine framework (CTF-1) Z-scheme heterojunction photocatalyst was rationally designed for antibiotics degradation under visible light irradiation. The NiFe-LDH/CTF-1 nanocomposites were readily obtained via in situ loading of NiFe-LDH on CTF-1 through covalent linking. The abundant coupling interfaces between two semiconductor counterparts lay the foundation for the formation of Z-scheme heterostructure, thereby effectively promoting the transfer of photogenerated electrons, inhibiting the recombination of carriers, as well as conferring the nanocomposites with stronger redox ability. Consequently, the optimal photocatalytic activity of the LDH/CTF heterojunction was significantly boosted for the degradation of a typical antibiotic, tetracycline (TC). Additionally, the photodegradation process and the mineralization of TC were further elucidated. These results envision that the LDH/CTF-1 can be a viable photocatalyst for long-term and sustainable wastewater treatment. Full article

The aromatic structure and the rich nitrogen content of polymers based on covalent triazine-based frameworks (CTF) and their unique hydrophilic-lipophilic-balanced adsorption properties make them promising candidates for an adsorbent that can be used for sample pretreatment. Herein, a new covalent triazine-based framework (CTF-DBF) synthesized by a Friedel–Crafts reaction was used for the determination of the content of nucleotides in commercial infant formula. It was shown that the synthetic materials had an amorphous microporous structure, a BET surface area of up to 595.59 m²/g, and 0.39 nm and 0.54 nm micropores. The versatile adsorption properties of this material were evaluated by quantum chemistry theory calculations and batch adsorption experiments using five nucleotides as probes. The quantum chemistry results demonstrated that CTF-DBF can participate in multiple interactions with nucleotides. All the analyses performed present good linearity with R² > 0.9993. The detection limits of targets ranged from 0.3 to 0.5 mg/kg, the spiked recoveries were between 85.8 and 105.3% and the relative standard deviations (RSD, n = 6) were between 1.1 and 4.5%. All these results suggest that this versatile CTF-DBF has great potential for sample pretreatment. Full article

Based on the recent (2015–2021) literature data, the authors analyze the mutual dependence of crystallinity/amorphism and specific surface area and porosity in covalent triazine frameworks (CTFs), taking into account thermodynamic and kinetic control in the synthesis of these 2D nanosheets. CTFs have now become a promising new class of high-performance porous organic materials. They can be recycled and reused easily, and thus have great potential as sustainable materials. For 2D CTFs, numerous examples are given to support the known rule that the structure and properties of any material with a given composition depend on the conditions of its synthesis. The review may be useful for elder students, postgraduate students, engineers and research fellows dealing with chemical synthesis and modern nanotechnologies based on 2D covalent triazine frameworks. Full article