Canakkale Onsekiz Mart University, Department of Chemical Engineering, 17100 Çanakkale, Türkiye.
Canakkale Onsekiz Mart University, Department of Energy Resources and Management, 17100 Çanakkale, Türkiye.
ACS Appl Mater Interfaces. 2023 Apr 19;15(15):18836-18844. doi: 10.1021/acsami.2c23233. Epub 2023 Apr 5.
Covalent organic frameworks (COFs) have shown promise in the field of photocatalysts for hydrogen evolution. Many studies have been carried out using various electroactive and photoactive moieties such as triazine, imide, and porphyrin to produce COFs with different geometric structures and units. Electron transfer mediators like viologen and their derivatives can accelerate the transfer of electrons from photosensitizers to active sites. Herein, the combination of a biphenyl-bridged dicarbazole electroactive donor skeleton with a viologen acceptor structure is reported for the photocatalytic hydrogen evolution of novel COF structures with various alkyl linkers {TPCBP X-COF [X = ethyl (E), butyl (B), and hexyl (H)]}. The structures became more flexible and exhibited less crystal behavior as the length of the alkyl chain increased according to scanning and transmission electron microscopy images, X-ray diffraction analyses, and theoretical three-dimensional geometric optimization. In comparison, the H evolution rate of the TPCBP B-COF (12.276 mmol g) is 2.15 and 2.38 times higher than those of the TPCBP H-COF (5.697 mmol h) and TPCBP E-COF (5.165 mmol h), respectively, under visible light illumination for 8 h. The TPCBP B-COF structure is one of the best-performing catalysts for the corresponding photocatalytic hydrogen evolution in the literature, producing 1.029 mmol g h with a high apparent quantum efficiency of 79.69% at 470 nm. Our strategy provides new aspects for the design of novel COFs with respect to future metal-free hydrogen evolution by using solar energy conversion.
共价有机骨架（COFs）在光催化制氢领域表现出了良好的应用前景。许多研究使用各种电活性和光活性基团，如三嗪、酰亚胺和卟啉，以产生具有不同几何结构和单元的 COFs。电子转移介体，如联吡啶及其衍生物，可以加速电子从光敏剂向活性位点的转移。在此，报告了一种联苯桥联二咔唑电活性供体骨架与一个联吡啶受体结构的组合，用于新型 COF 结构的光催化析氢，这些 COF 结构具有各种烷基链接 {TPCBP X-COF [X = 乙基（E）、丁基（B）和己基（H）]}。根据扫描和透射电子显微镜图像、X 射线衍射分析和理论三维几何优化，结构变得更加灵活，随着烷基链长度的增加，晶体行为减少。相比之下，在可见光照射 8 小时后，TPCBP B-COF（12.276 mmol g）的 H 析出率分别比 TPCBP H-COF（5.697 mmol h）和 TPCBP E-COF（5.165 mmol h）高 2.15 和 2.38 倍。TPCBP B-COF 结构是文献中相应光催化析氢性能最好的催化剂之一，在 470nm 时，其表观量子效率为 79.69%，产氢量为 1.029mmol g h。我们的策略为利用太阳能转化设计新型 COFs 提供了新的思路，以实现未来的无金属制氢。
