Rational design of graphic carbon nitride copolymers by molecular doping for visible-light-driven degradation of aqueous sulfamethazine and hydrogen evolution
Rational design of graphic carbon nitride copolymers by molecular doping for visible-light-driven degradation of aqueous sulfamethazine and hydrogen evolution
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DOI：
10.1016/j.cej.2018.11.140
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发表时间：
2019-03
影响因子：
15.1
通讯作者：
Chengyun Zhou;Piao Xu;Cui Lai;Chen Zhang;G. Zeng;Danlian Huang;Min Cheng;L. Hu;Weiping Xiong-Weiping-Xi
中科院分区：
文献类型：
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作者：
Chengyun Zhou;Piao Xu;Cui Lai;Chen Zhang;G. Zeng;Danlian Huang;Min Cheng;L. Hu;Weiping Xiong-Weiping-Xi
氮化碳是一种很有前途的无金属可见光催化剂和可持续材料，用于解决污染物污染和水分解。然而，氮化碳的可见光吸收不足和快速电荷复合限制了其实际应用。本文以尿素和2-硫代巴比妥酸（TA）为原料，通过分子掺杂共聚制备了自组装氮化碳（TCN）。XPS和元素分析结果表明，TA成功地掺杂到了氮化碳的骨架中。自组装共聚反应会导致氮化碳的形貌、本征电子和能带结构发生变化。理论计算和实验证实，TCN的带隙可以通过改变2-硫代巴比妥酸的量来调节。此外，载流子转移和分离的效率大大提高。结果表明，优化后的TCN-0.03光催化剂在可见光照射下对磺胺二甲嘧啶的降解反应速率高达0.058 min-1，是尿素基氮化碳（U-CN）的4.2倍，表现出优异的上级活性。作为一种多功能光催化剂，TCN-0.03表现出更高的产氢活性（55 μmol h−1），是U-CN的11倍。在420 nm处，表观量子效率达到4.8%。提出了一种可能的机理来解释光催化反应过程。本工作为合理设计其他有机单体共聚改性氮化碳以提高其光催化活性提供了思路。
Carbon nitride is a promising metal-free visible light driven photocatalyst and sustainable material for address contaminant pollution and water splitting. However, the insufficient visible light absorption and fast charge recombination of carbon nitride have limited its practical application. Herein, the self-assembly carbon nitride (denoted as TCN) by molecular doping copolymerization of urea and 2-thiobarbitucid acid (TA) was prepared. XPS and elemental analytical results indicated that TA was doped in the framework of carbon nitride successfully. The self-assembly copolymerization would result in the change of morphology, intrinsic electron and band structure of carbon nitride. Theoretical calculations and experiments confirm that the band gap of TCN could be adjusted by changing the amount of 2-thiobarbitucid acid. Moreover, the efficiency of charge carrier transfer and separation was greatly enhanced. As a result, the optimized photocatalyst TCN-0.03 exhibited superior activity with a high reaction rate of 0.058 min−1for the degradation of sulfamethazine under visible light irradiation, which is 4.2 times higher than that of urea based carbon nitride (U-CN). As a multifunctional photocatalyst, TCN-0.03 showed enhanced activity for hydrogen production (55 μmol h−1), which was 11 times higher than U-CN. The apparent quantum efficiency reached to 4.8% at 420 nm. A possible mechanism was proposed to explain the photocatalytic reaction process. This work provides insight into the rational design of modified carbon nitride by other organic monomers copolymerization to enhance the photocatalytic activity.