Zhang Hualei, Lin Zheng, Guo Jia
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University Shanghai 200433 China
RSC Adv. 2022 May 18;12(23):14932-14938. doi: 10.1039/d2ra02236b. eCollection 2022 May 12.
Covalent organic frameworks (COFs) have been investigated in the field of photocatalysts for H evolution because of their crystalline structure and diversity. However, most of them need the help of noble metals as co-catalysts to realize a high hydrogen evolution. Herein, we chose typical COFs as a platform and constructed NiS-BD (: weight fraction of NiS) composites by assembling NiS at room temperature. The NiS nanoparticles are shown to tightly adhere to the COFs surface. Under visible light irradiation (wavelength > 420 nm), the optimized sample with 3 wt% NiS loading exhibits a photocatalytic H evolution rate of 38.4 μmol h (3840 μmol h g), which is about 120 folds higher than that of the pure TpBD-COF and better than TpBD-COF/Pt with the same Pt loading (3 wt%). NiS3-BD shows stable hydrogen evolution in at least six consecutive cycle tests totaling 18 h. Further investigation reveals that the loaded NiS can facilitate the transfer of photogenerated electrons from TpBD-COF to the co-catalyst, leading to efficient and high photocatalytic activity. Combining the significant feature of COFs, this study opens up a feasible avenue to boost the photocatalytic H performance by constructing the synergetic effects between COFs and cost-effective material.
共价有机框架（COFs）因其晶体结构和多样性，已在光催化剂制氢领域得到研究。然而，它们中的大多数需要贵金属作为助催化剂来实现高析氢量。在此，我们选择典型的COFs作为平台，通过在室温下组装硫化镍构建了NiS-BD（：硫化镍的重量分数）复合材料。结果表明，硫化镍纳米颗粒紧密附着在COFs表面。在可见光照射（波长>420nm）下，负载量为3wt%硫化镍的优化样品表现出38.4μmol h（3840μmol h g）的光催化析氢速率，这比纯TpBD-COF高出约120倍，且优于相同铂负载量（3wt%）的TpBD-COF/Pt。NiS3-BD在总共18小时的至少六个连续循环测试中显示出稳定的析氢性能。进一步研究表明，负载的硫化镍可以促进光生电子从TpBD-COF转移到助催化剂，从而产生高效的光催化活性。结合COFs的显著特性，本研究通过构建COFs与经济高效材料之间的协同效应，开辟了一条提高光催化析氢性能的可行途径。
