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2D N-Doped Porous Carbon Derived from Polydopamine-Coated Graphitic Carbon Nitride for Efficient Nonradical Activation of Peroxymonosulfate.
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2020-06-08 , DOI: 10.1021/acs.est.0c03207
Jie Miao 1 , Wei Geng 1 , Pedro J J Alvarez 2 , Mingce Long 1
Affiliation  

Nitrogen-doped carbon materials attract broad interest as catalysts for peroxymonosulfate (PMS) activation toward an efficient, nonradical advanced oxidation process. However, synthesis of N-rich carbocatalysts is challenging because of the thermal instability of desirable nitrogenous species (pyrrolic, pyridinic, and graphitic N). Furthermore, the relative importance of different nitrogenous configurations (and associated activation mechanisms) are unclear. Herein, we report a “coating-pyrolysis” method to synthesize porous 2D N-rich nanocarbon materials (PCN-x) derived from dopamine and g-C3N4 in different weight proportions. PCN-0.5 calcined at 800 °C had the highest surface area (759 m2/g) and unprecedentedly high N content (18.5 at%), and displayed the highest efficiency for 4-chlorophenol (4-CP) degradation via PMS activation. A positive correlation was observed between 4-CP oxidation rates and the total pyridinic and pyrrolic N content. These N dopants serve as Lewis basic sites to facilitate 4-CP adsorption on the PCN surface and subsequent electron-transfer from 4-CP to PMS, mediated by surface-bound complexes (PMS–PCN-0.5). The main degradation products were chlorinated oligomers (mostly dimeric biphenolic compounds), which adsorbed to and deteriorated the carbocatalyst. Overall, this study offers new insights for rational design of nitrogen-enriched carbocatalysts, and advances mechanistic understanding of the critical role of N species during nonradical PMS activation.

中文翻译:

从聚多巴胺涂层的石墨碳氮化物中衍生的二维N掺杂多孔碳,用于过氧单硫酸盐的有效非自由基活化。

氮掺杂碳材料作为过氧单硫酸盐(PMS)活化朝着有效的,非自由基的高级氧化过程的催化剂,引起了广泛的兴趣。但是,由于所需含氮物质(吡咯,吡啶和石墨N)的热不稳定性,富N碳催化剂的合成具有挑战性。此外,不清楚不同的含氮构型(和相关的激活机制)的相对重要性。在本文中,我们报道了一种“涂覆-热解”方法,以合成来自多巴胺和gC 3 N 4的不同重量比例的多孔2D富N纳米碳材料(PCN- x)。在800°C下煅烧的PCN-0.5具有最大表面积(759 m 2/ g)和前所未有的高N含量(18.5 at%),并显示了通过PMS活化降解4-氯苯酚(4-CP)的最高效率。在4-CP氧化速率与总吡啶和吡咯N含量之间观察到正相关。这些N掺杂剂充当Lewis碱性位点,以促进4-CP在PCN表面上的吸附以及随后由表面结合的复合物(PMS-PCN-0.5)介导的从4-CP到PMS的电子转移。主要降解产物是氯化低聚物(大多数为二聚双酚化合物),它吸附并降解了碳催化剂。总的来说,这项研究为富氮碳催化剂的合理设计提供了新的见识,并提高了对非自由基PMS活化过程中N物种的关键作用的机械理解。
更新日期:2020-07-07
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