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Covalent triazine frameworks (CTFs) are a class of unique two-dimensional nitrogen-rich triazine framework with adjustable chemical and electronic structures, rich porosity, good stability and excellent semiconductivity, which enable great various applications in efficient gas/molecular adsorption and separation, energy storage and conversion, especially photo- and electro-catalysis. Different synthesis strategies strongly affect the morphology of CTFs and play an important role in their structure and properties. In this concept, we provide a comprehensive and systematic review of the synthesis methods such as ionothermal synthesis, phosphorus pentoxide catalytic method, polycondensation and ultra-strong acid catalyzed method, and applications of CTFs in photo- and electro-catalysis. Finally we offer some insights into the future development progress of CTFs materials for catalytic applications.
Qian, Z. F.; Wang, Z. J.; Zhang, K. A. I. Covalent triazine frameworks as emerging heterogeneous photocatalysts. Chem. Mater. 2021, 33, 1909–1926.
Liu, M. Y.; Guo, L. P.; Jin, S. B.; Tan, B. E. Covalent triazine frameworks: Synthesis and applications. J. Mater. Chem. A 2019, 7, 5153–5172.
Sun, R. X.; Tan, B. E. Covalent triazine frameworks (CTFs): Synthesis, crystallization, and photocatalytic water splitting. Chem.—Eur. J. 2023, 29, e202203077.
Haldar, S.; Waentig, A. L.; Ramuglia, A. R.; Bhauriyal, P.; Khan, A. H.; Pastoetter, D. L.; Isaacs, M. A.; De, A.; Brunner, E.; Wang, M. C. et al. Covalent trapping of cyclic-polysulfides in perfluorinated vinylene-linked frameworks for designing lithium-organosulfide batteries. ACS Energy Lett. 2023, 8, 5098–5106.
Shao, J. L.; Zhou, Z. F.; Chen, X.; Tian, R. Y.; Zhang, Z. H.; Li, G. C. Pseudo-covalent triazine frameworks for superior Li-S batteries. Chem. Eng. J. 2024, 481, 148209.
Wu, Y. A.; McNulty, I.; Liu, C.; Lau, K. C.; Liu, Q.; Paulikas, A. P.; Sun, C. J.; Cai, Z. H.; Guest, J. R.; Ren, Y. et al. Facet-dependent active sites of a single Cu2O particle photocatalyst for CO2 reduction to methanol. Nat. Energy 2019, 4, 957–968.
Li, Y. X.; Lai, C.; Liu, S. B.; Fu, Y. K.; Qin, L.; Xu, M. Y.; Ma, D. S.; Zhou, X. R.; Xu. F. H.; Liu, H. D. et al. Metallic active-site engineering: A bridge between covalent triazine frameworks and high-performance catalysts. J. Mater. Chem. A 2023, 11, 2070–2091.
Yang, S.; Gao, Z.; Hu, Z. Y.; Pan, C. Y.; Yuan, J. Y.; Tam, K. C.; Liu, Y. N.; Yu, G. P.; Tang, J. T. Regulating the tautomerization in covalent organic frameworks for efficient sacrificial agent-free photocatalytic H2O2 production. Macromolecules 2024, 57, 2039–2047.
Niu, Q.; Mi, L. H.; Chen, W.; Li, Q. J.; Zhong, S. H.; Yu, Y.; Li, L. Y. Review of covalent organic frameworks for single‐site photocatalysis and electrocatalysis. Chin. J. Catal. 2023, 50, 45–82.
Xing, Z. P.; Zhang, J. Q.; Cui, J. Y.; Yin, J. W.; Zhao, T. Y.; Kuang, J. Y.; Xiu, Z. Y.; Wan, N.; Zhou, W. Recent advances in floating TiO2-based photocatalysts for environmental application. Appl. Catal. B: Envrion. Energy 2018, 225, 452–467.
Kuhn, P.; Antonietti, M.; Thomas, A. Porous, covalent triazine-based frameworks prepared by ionothermal synthesis. Angew. Chem., Int. Ed. 2008, 47, 3450–3453.
Abednatanzi, S.; Derakhshandeh, P. G.; Tack, P.; Muniz-Miranda, F.; Liu, Y. Y.; Everaert, J.; Meledina, M.; Bussche, F. V.; Vincze, L.; Stevens, C. V. et al. Elucidating the promotional effect of a covalent triazine framework in aerobic oxidation. Appl. Catal. B: Envrion. Energy 2020, 269, 118769.
Zhen, J. H.; Shen, J. C.; Sun, T.; Wang, C. X.; Lyu, P. B.; Xu, Y. X. Direct synthesis of ultrathin crystalline two-dimensional triazine polymers from aldoximes. CCS Chem. 2024, 6, 932–940.
Liang, Z. Z.; Shen, R. C.; Ng, Y. H.; Fu, Y.; Ma, T. Y.; Zhang, P.; Li, Y. J.; Li, X. Covalent organic frameworks: Fundamentals, mechanisms, modification, and applications in photocatalysis. Chem Catal. 2022, 2, 2157–2228.
Hasija, V.; Patial, S.; Raizada, P.; Khan, A. A. P.; Asiri, A. M.; Van Le, Q.; Nguyen, V. H.; Singh, P. Covalent organic frameworks promoted single metal atom catalysis: Strategies and applications. Coord. Chem. Rev. 2022, 452, 214298.
Liu, S. S.; Wang, M. F.; He, Y. Z.; Cheng, Q. Y.; Qian, T.; Yan, C. L. Covalent organic frameworks towards photocatalytic applications: Design principles, achievements, and opportunities. Coord. Chem. Rev. 2023, 475, 214882.
Xiang, Z. H.; Cao, D. P.; Huang, L.; Shui, J. L.; Wang, M.; Dai, L. M. Nitrogen-doped holey graphitic carbon from 2D covalent organic polymers for oxygen reduction. Adv. Mater. 2014, 26, 3315–3320.
Nowsheenah, F.; Abu, T.; Athar, A. H. Facile synthesis of a nitrogen-rich covalent organic framework for the efficient capture of iodine. J. Mater. Chem. A 2024, 12, 10539–10553.
Patial, S.; Soni, V.; Kumar, A.; Raizada, P.; Ahamad, T.; Pham, X. M.; Le, Q. V.; Nguyen, V. H.; Thakur, S.; Singh, P. Rational design, structure properties, and synthesis strategies of dual-pore covalent organic frameworks (COFs) for potent applications: A review. Environ. Res. 2023, 218, 114982.
Dong, B.; Wang, D. Y.; Wang, W. J. Post-functionalization of hydroxyl-appended covalent triazine framework via borrowing hydrogen strategy for effective CO2 capture. Micropor. Mesopor. Mat. 2020, 292, 109765.
Liu, Y. B.; Wu, H.; Wang, Q. Strategies to improve the photocatalytic performance of covalent triazine frameworks. J. Mater. Chem. A 2023, 11, 21470–21497.
Liao, L. F.; Li, M. Y.; Yin, Y. L.; Chen, J.; Zhong, Q. T.; Du, R. X.; Liu, S. L.; He, Y. M.; Fu, W. J.; Zeng, F. Advances in the synthesis of covalent triazine frameworks. ACS Omega 2023, 8, 4527–4542.
Kuhn, P.; Forget, A.; Hartmann, J.; Thomas, A.; Antonietti, M. Template-free tuning of nanopores in carbonaceous polymers through ionothermal synthesis. Adv. Mater. 2009, 21, 897–901.
Kuhn, P.; Forget, A.; Su, D. S.; Thomas, A.; Antonietti, M. From microporous regular frameworks to mesoporous materials with ultrahigh surface area: Dynamic reorganization of porous polymer networks. J. Am. Chem. Soc. 2008, 130, 13333–13337.
Kuhn, P.; Thomas, A.; Antonietti, M. Toward tailorable porous organic polymer networks: A high-temperature dynamic polymerization scheme based on aromatic nitriles. Macromolecules 2009, 42, 319–326.
Cui, K.; Tang, X. L.; Xu, X. P.; Kou, M. C.; Lyu, P. B.; Xu, Y. X. Crystalline dual-porous covalent triazine frameworks as a new platform for efficient electrocatalysis. Angew. Chem., Int. Ed. 2024, 63, e202317664.
Yu, S. Y.; Mahmood, J.; Noh, H. J.; Seo, J. M.; Jung, S. M.; Shin, S. H.; Im, Y. K.; Jeon, I. Y.; Baek, J. B. Direct synthesis of a covalent triazine-based framework from aromatic amides. Angew. Chem., Int. Ed. 2018, 57, 8438–8442.
Sun, R. X.; Wang, X. Y.; Wang, X. P.; Tan, B. Three-dimensional crystalline covalent triazine frameworks via a polycondensation approach. Angew. Chem., Int. Ed. 2022, 61, e202117668.
Ren, S. J.; Bojdys, M. J.; Dawson, R.; Laybourn, A.; Khimyak, Y. Z.; Adams, D. J.; Cooper, A. I. Porous, fluorescent, covalent triazine-based frameworks via room-temperature and microwave-assisted synthesis. Adv. Mater. 2012, 24, 2357–2361.
Yang, Z. Z.; Chen, H.; Wang, S.; Guo, W.; Wang, T.; Suo, X.; Jiang, D. E.; Zhu, X.; Popovs, I.; Dai, S. Transformation strategy for highly crystalline covalent triazine frameworks: From staggered AB to eclipsed AA stacking. J. Am. Chem. Soc. 2020, 142, 6856–6860.
Xiao, L. Y.; Qi, L. L.; Sun, J. R.; Husile, A.; Zhang, S. Y.; Wang, Z. L.; Guan, J. Q. Structural regulation of covalent organic frameworks for advanced electrocatalysis. Nano Energy 2024, 120, 109155.
Li, S.; Wu, M. F.; Guo, T.; Zheng, L. L.; Wang, D. K.; Mu, Y.; Xing, Q. J.; Zou, J. P. Chlorine-mediated photocatalytic hydrogen production based on triazine covalent organic framework. Appl. Catal. B: Environ. 2020, 272, 118989.
Chen, M. H.; Xiong, J.; Li, X. Y.; Shi, Q.; Li, T.; Feng, Y. Q.; Zhang, B. In-situ doping strategy for improving the photocatalytic hydrogen evolution performance of covalent triazine frameworks. Sci. China Chem. 2023, 66, 2363–2370
Jana, A.; Maity, A.; Sarkar, A.; Show, B.; Bhobe, P. A.; Bhunia, A. Single-site cobalt catalyst embedded in a covalent triazine-based framework (CTF) for photocatalytic CO2 reduction. J. Mater. Chem. A 2024, 12, 5244–5253.
Sun, R. X.; Hu, X. L.; Shu, C.; Zheng, L. R.; Wang, S. Y.; Wang, X. Y.; Tan, B. E. Anchoring single Co sites on bipyridine-based covalent triazine framework for efficient photocatalytic oxygen evolution. Chin. J. Catal. 2023, 55, 159–170.
Chen, H. M.; Gardner, A. M.; Lin, G. A.; Zhao, W.; Bahri, M.; Browning, N. D.; Sprick, R. S.; Li, X. B.; Xu, X. X.; Cooper, A. I. Covalent triazine-based frameworks with cobalt-loading for visible light-driven photocatalytic water oxidation. Catal. Sci. Technol. 2022, 12, 5442–5452.
Li, Z. L.; Li, T. C.; Miao, J. M.; Zhao, C. X.; Jing, Y.; Han, F. Y.; Zhang, K.; Yang, X. F. Amide-functionalized covalent triazine framework for enhanced photocatalytic hydrogen evolution. Sci. China Mater. 2023, 66, 2290–2298.
Wang, X. Y.; Fu, Z. W.; Zheng, L. R.; Zhao, C. X.; Wang, X.; Chong, S. Y.; McBride, F.; Raval, R.; Bilton, M.; Liu, L. J. et al. Covalent organic framework nanosheets embedding single cobalt sites for photocatalytic reduction of carbon dioxide. Chem. Mater. 2020, 32, 9107–9114.
Zhang, S. Q.; Wang, S. Y.; Guo, L. P.; Chen, H.; Tan, B. E.; Jin, S. B. An artificial photosynthesis system comprising a covalent triazine framework as an electron relay facilitator for photochemical carbon dioxide reduction. J. Mater. Chem. C 2020, 8, 192–200.
Kosugi, K.; Akatsuka, C.; Iwami, H.; Kondo, M.; Masaoka, S. Iron-complex-based supramolecular framework catalyst for visible-light-driven CO2 reduction. J. Am. Chem. Soc. 2023, 145, 10451–10457.
Sun, R. X.; Tan, B. E. Covalent triazine frameworks (CTFs) for photocatalytic applications. Chem. Res. Chin. Univ. 2022, 38, 310–324.
Huang, W.; He, Q.; Hu, Y. P.; Li, Y. G. Molecular heterostructures of covalent triazine frameworks for enhanced photocatalytic hydrogen production. Angew. Chem., Int. Ed. 2019, 58, 8676–8680.
Zhao, Y. X.; Chang, C.; Teng, F.; Zhao, Y. F.; Chen, G. B.; Shi, R.; Waterhouse, G. I. N.; Huang, W. F.; Zhang, T. R. Defect-engineered ultrathin δ-MnO2 nanosheet arrays as bifunctional electrodes for efficient overall water splitting. Adv. Energy Mater. 2017, 7, 1700005.
Lan, Z. A.; Chi, X.; Wu, M.; Zhang, X. R.; Chen, X.; Zhang, G. G.; Wang, X. C. Molecular design of covalent triazine frameworks with anisotropic charge migration for photocatalytic hydrogen production. Small 2022, 18, 2200129.
Buyukcakir, O.; Je, S. H.; Talapaneni, S. N.; Kim, D.; Coskun, A. Charged covalent triazine frameworks for CO2 capture and conversion. ACS Appl. Mater. Interfaces 2017, 9, 7209–7216.
Zhu, H.; Lin, W. J.; Li, Q.; Hu, Y.; Guo, S. Y.; Wang, C. M.; Yan, F. Bipyridinium-based ionic covalent triazine frameworks for CO2, SO2, and NO capture. ACS Appl. Mater. Interfaces 2020, 12, 8614–8621.
Zhang, G. P.; Li, X. X.; Chen, D. Y.; Li, N. J.; Xu, Q. F.; Li, H.; Lu, J. M. Internal electric field and adsorption effect synergistically boost carbon dioxide conversion on cadmium sulfide@covalent triazine frameworks core–shell photocatalyst. Adv. Funct. Mater. 2023, 33, 2308553.
Meng, A. Y.; Cheng, B.; Tan, H. Y.; Fan, J. J.; Su, C. L.; Yu, J. G. TiO2/polydopamine S-scheme heterojunction photocatalyst with enhanced CO2-reduction selectivity. Appl. Catal. B: Environ. 2021, 289, 120039.
Xu, F. Y.; Meng, K.; Cheng, B.; Wang, S. Y.; Xu, J. S.; Yu, J. G. Unique S-scheme heterojunctions in self-assembled TiO2/CsPbBr3 hybrids for CO2 photoreduction. Nat. Commun. 2020, 11, 4613.
Wang, L. B.; Fei, X. G.; Zhang, L. Y.; Yu, J. G.; Cheng, B.; Ma, Y. H. Solar fuel generation over nature-inspired recyclable TiO2/g-C3N4 S-scheme hierarchical thin-film photocatalyst. J. Mater. Sci. Technol. 2022, 112, 1–10.
Hu, J. D.; Yang, T. Y.; Yang, X. G.; Qu, J. F.; Cai, Y. H.; Li, C. M. Highly selective and efficient solar-light-driven CO2 conversion with an ambient-stable 2D/2D Co2P@BP/g-C3N4 heterojunction. Small 2022, 18, 2105376.
Wang, L.; Wang, L.; Xu, Y. K.; Sun, G. X.; Nie, W. C.; Liu, L. H.; Kong, D. B.; Pan, Y.; Zhang, Y. H.; Wang, H. et al. Schottky junction and D-A1-A2 system dual regulation of covalent triazine frameworks for highly efficient CO2 photoreduction. Adv. Mater. 2024, 36, 2309376.
Wisser, F. M.; Duguet, M.; Perrinet, Q.; Ghosh, A. C.; Alves-Favaro, M.; Mohr, Y.; Lorentz, C.; Quadrelli, E. A.; Palkovits, R.; Farrusseng, D. et al. Molecular porous photosystems tailored for long-term photocatalytic CO2 reduction. Angew. Chem., Int. Ed. 2020, 59, 5116–5122.
Huang, G. C.; Lin, G. Y.; Niu, Q.; Bi, J. H.; Wu, L. Covalent triazine-based frameworks confining cobalt single atoms for photocatalytic CO2 reduction and hydrogen production. J. Mater. Sci. Technol. 2022, 116, 41–49.
Huang, G. C.; Niu, Q.; He, Y. X.; Tian, J. J.; Gao, M. B.; Li, C. Y.; An, N.; Bi, J. H.; Zhang, J. W. Spatial confinement of copper single atoms into covalent triazine-based frameworks for highly efficient and selective photocatalytic CO2 reduction. Nano Res. 2022, 15, 8001–8009.
Hu, X. L.; Zheng, L. R.; Wang, S. Y.; Wang, X. Y.; Tan. B. Integrating single Co sites into crystalline covalent triazine frameworks for photoreduction of CO2. Chem. Commun. 2022, 58, 8121–8124.
Yi, J. D.; Li, Q. X.; Chi, S. Y.; Huang, Y. B.; Cao, R. Boron-doped covalent triazine framework for efficient CO2 electroreduction. Chem. Res. Chin. Univ. 2022, 38, 141–146.
Suo, X.; Zhang, F. T.; Yang, Z. Z.; Chen, H.; Wang, T.; Wang, Z. Y.; Kobayashi, T.; Do-Thanh, C. L.; Maltsev, D.; Liu, Z. M. et al. Highly perfluorinated covalent triazine frameworks derived from a low-temperature ionothermal approach towards enhanced CO2 electroreduction. Angew. Chem., Int. Ed. 2021, 60, 25688–25694.
Wang, C. X.; Zhang, H. L.; Luo, W. J.; Sun, T.; Xu, Y. X. Ultrathin crystalline covalent-triazine-framework nanosheets with electron donor groups for synergistically enhanced photocatalytic water splitting. Angew. Chem., Int. Ed. 2021, 60, 25381–25390.
Gao, P. P.; Wu, C. B.; Wang, S. Y.; Zheng, G. F.; Han, Q. Efficient photosynthesis of hydrogen peroxide by triazole-modified covalent triazine framework nanosheets. J. Colloid Interface Sci. 2023, 650, 40–46.
Huang, G. C.; Niu, Q.; Zhang, J. W.; Huang, H. M.; Chen, Q. S.; Bi, J. H.; Wu, L. Platinum single-atoms anchored covalent triazine framework for efficient photoreduction of CO2 to CH4. Chem. Eng. J. 2022, 427, 131018.
Tao, Y.; Yang, D. H.; Kong, H. Y.; Wang, T. X.; Li, Z. H.; Ding, X. S.; Han, B. H. Covalent triazine polymer derived porous carbon with high porosity and nitrogen content for bifunctional oxygen catalysis in zinc-air battery. Appl. Catal. B: Environ. 2023, 339, 123088.
Li, N. N.; Tang, R. Z.; Su, Y. Z.; Lu, C. B.; Chen, Z. M.; Sun, J.; Lv, Y. Q.; Han, S.; Yang, C. Q.; Zhuang, X. D. Isometric covalent triazine framework-derived porous carbons as metal-free electrocatalysts for the oxygen reduction reaction. ChemSusChem 2023, 16, e202201937.
Zheng, Y.; Chen, S.; Zhang, K. A. I.; Zhu, J. X.; Xu, J. S.; Zhang, C.; Liu, T. X. Ultrasound-triggered assembly of covalent triazine framework for synthesizing heteroatom-doped carbon nanoflowers boosting metal-free bifunctional electrocatalysis. ACS Appl. Mater. Interfaces 2021, 13, 13328–13337.
Allwyn, N.; Ambrose, B.; Kathiresan, M.; Sathish, M. Self-sacrificial templated nanoarchitectonics of nitrogen-doped carbon derived from viologen-based covalent triazine polymer: An oxygen reduction electrocatalyst in zinc-air batteries. ACS Appl. Energy Mater. 2023, 6, 11408–11419.
Pan, Y.; Xin, Y. P.; Li, Y. H.; Xu, Z.; Tang, C.; Liu, X.; Yin, Y. C.; Zhang, J. C.; Xu, F. G.; Li, C. et al. Nitrogen-doped carbon cubosomes as an efficient electrocatalyst with high accessibility of internal active sites. ACS Nano 2023, 17, 23850–23860.
Song, K. S.; Talapaneni, S. N.; Ashirov, T.; Coskun, A. Molten salt templated synthesis of covalent isocyanurate frameworks with tunable morphology and high CO2 uptake capacity. ACS Appl. Mater. Interfaces 2021, 13, 26102–26108.
Sun, L.; Yang, M.; Guo, H.; Zhang, T. T.; Wu, N.; Wang, M. Y.; Yang, F.; Zhang, J. Y.; Yang, W. COOH-MWCNT connected COF and chemical activated CTF as a novel electrochemical sensing platform for simultaneous detection of acetaminophen and p-aminophenol. Colloids Surf. A Physicochem. Eng. Aspects 2022, 647, 129092.
Sun, L.; Guo, H.; Pan, Z. L.; Liu, B. Q.; Wu, N.; Liu, Y. S.; Lu, Z. Y.; Wei, X. Q.; Yang, W. Design of NiCo2O4 nanoflowers decorated sulfurbridged covalent triazine frameworks nanocomposites for electrochemical simultaneous detection of acetaminophen and 4-aminophenol. Microchem. J. 2022, 182, 107879.
Zhu, X. J.; Dai, J. L.; Li, L. G.; Wu, Z. X.; Chen, S. W. N. S-codoped hierarchical porous carbon spheres embedded with cobalt nanoparticles as efficient bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries. Nanoscale 2019, 11, 21302–21310
Li, M. J.; Lv, M. H.; Zheng, Y.; Zhu, M. M.; Feng, Q. C.; Guan, J. Y.; Yu, X. H.; Shen, Y.; Hou, J. H.; Lu, Y. et al. Bimetallic-coordinated covalent triazine framework-derived FeNi alloy nanoparticle-decorated coral-like nanocarbons for oxygen electrocatalysis. ACS Appl. Mater. Interfaces 2024, 16, 633–642.
Zhu, Y. Z.; Chen, X. F.; Liu, J.; Zhang, J. F.; Xu, D. Y.; Peng, W. C.; Li, Y.; Zhang, G. L.; Zhang, F. B.; Fan, X. B. Rational design of Fe/N/S-doped nanoporous carbon catalysts from covalent triazine frameworks for efficient oxygen reduction. ChemSusChem 2018, 11, 2402–2409.
Zheng, Y.; Chen, S.; Zhang, K. A. I.; Guan, J. Y.; Yu, X. H.; Peng, W.; Song, H.; Zhu, J. X.; Xu, J. S.; Fan, X. S. et al. Template-free construction of hollow mesoporous carbon spheres from a covalent triazine framework for enhanced oxygen electroreduction. J. Colloid Interface Sci. 2022, 608, 3168–3177.
Jena, H. S.; Krishnaraj, C.; Satpathy, B. K.; Rawat, K. S.; Leus, K.; Veerapandian, S.; Morent, R.; De Geyter, N.; Van Speybroeck, V.; Pradhan, D. et al. Phosphorus covalent triazine framework-based nanomaterials for electrocatalytic hydrogen evolution reaction. ACS Appl. Nano Mater. 2023, 6, 22684–22692.
Zhang, J.; Xu, Y. P.; Lan, M. W.; Wang, X. D.; Fu, N.; Yang, Z. L. Heteroatom-doped carbon materials derived from covalent triazine framework@MOFs for the oxygen reduction reaction. Dalton Trans. 2022, 51, 14482–14490.
Khan, R.; Chakraborty, J.; Rawat, K. S.; Morent, R.; De Geyter, N.; Van Speybroeck, V.; Van Der Voort, P. Super-oxidizing covalent triazine framework electrocatalyst for two-electron water oxidation to H2O2. Angew. Chem., Int. Ed. 2023, 62, e202313836.
Huo, L. P.; Lv, M. H.; Li, M. J.; Ni, X. P.; Guan, J. Y.; Liu, J.; Mei, S. X.; Yang, Y. Q.; Zhu, M. M.; Feng, Q. C. et al. Amorphous MnO2 lamellae encapsulated covalent triazine polymer-derived multi-heteroatoms-doped carbon for ORR/OER bifunctional electrocatalysis. Adv. Mater. 2024, 36, 2312868.