Tunable Nitrogen Defects on Graphitic Carbon Nitride toward the Visible-Light-Induced Reversible-Deactivation Radical Polymerization,Macromolecules

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Tunable Nitrogen Defects on Graphitic Carbon Nitride toward the Visible-Light-Induced Reversible-Deactivation Radical Polymerization
Macromolecules ( IF 5.1 ) Pub Date : 2022-06-20 , DOI: 10.1021/acs.macromol.2c01099
Shiwei Han ₁ , Teng Qiu _{1,

2} , Chongwen Xiong ₁ , Xiaoyu Li _{1,

2} , Longhai Guo _{1,

2,

3}

Affiliation

Introducing nitrogen defects has been confirmed to improve the photoactivity of graphitic carbon nitride, but this strategy is far from being employed in the field of photo-polymerization. Here, the nitrogen-deficient graphitic carbon nitride (g-C₃N_x) is proposed as an effective photocatalyst for photoinduced electron/energy transfer reversible addition–fragmentation chain transfer (PET-RAFT) polymerization under visible light. The g-C₃N_x was prepared through the thermal polymerization of melamine with the pre-treatment by using the different kinds of preparation tailoring agents (PTAs). It has been revealed that both the amount and the type of the PTA have a profound impact on the reaction rate and the induction period of this visible-light-driven PET-RAFT polymerization, attributed to modulating the optical absorption boundary and the carrier transport efficiency of g-C₃N_x by the introduced defects of nitrogen vacancies and cyano groups. Under the optimal condition with 0.5 g of NaOH being employed as the PTA, a monomer conversion higher than 90% was obtained in the PET-RAFT polymerization, almost doubled in comparison to the conversion catalyzed by pristine g-C₃N₄ under the parallel 10 h of blue light (λ_max = 465 nm) irradiation, and the induction period was also dramatically shortened. The as-synthesized polymers exhibit a kinetically controlled molecular weight with low dispersity (PDI < 1.2). Moreover, high end-group fidelity, universal monomer/chain transfer agent adaptation, and reliable reused capability are shown on the 2D sheets of g-C₃N_x being applied as the potential semiconductor catalyst for PET-RAFT polymerization under visible light.

中文翻译：

石墨氮化碳上的可调谐氮缺陷对可见光诱导的可逆失活自由基聚合

引入氮缺陷已被证实可以提高石墨氮化碳的光活性，但该策略远未应用于光聚合领域。在这里，缺氮石墨氮化碳（gC ₃ N _x）被认为是一种有效的光催化剂，用于在可见光下进行光致电子/能量转移可逆加成-断裂链转移（PET-RAFT）聚合。gC ₃ N _x采用不同种类的制备调节剂（PTA）通过三聚氰胺的热聚合和预处理制备。研究表明，PTA 的数量和类型对可见光驱动的 PET-RAFT 聚合的反应速率和诱导期都有深远的影响，这归因于调节光吸收边界和载流子传输效率gC ₃ N _x通过引入氮空位和氰基的缺陷。在使用 0.5 g NaOH 作为 PTA 的最佳条件下，PET-RAFT 聚合中的单体转化率高于 90%，与原始 gC ₃ N _{4催化的转化率相比几乎翻了一番}在蓝光（λ _max = 465 nm）平行照射10 h下，诱导期也显着缩短。合成后的聚合物表现出动力学控制的分子量和低分散性（PDI < 1.2）。_{此外，gC 3} N _x的二维片材显示出高端基保真度、通用单体/链转移剂适应性和可靠的重复使用能力，被用作可见光下 PET-RAFT 聚合的潜在半导体催化剂。

更新日期：2022-06-20

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