Accurate design of hollow/tubular porous g-C3N4 from melamine-cyanuric acid supramolecular prepared with mechanochemical method
Accurate design of hollow/tubular porous g-C3N4 from melamine-cyanuric acid supramolecular prepared with mechanochemical method
复制标题
机械化学法制备三聚氰胺-氰尿酸超分子空心/管状多孔g-C3N4的精确设计
DOI：
10.1016/j.cej.2020.128400
复制
发表时间：
2021-01-16
影响因子：
15.1
通讯作者：
Cai, Yaqi
中科院分区：
文献类型：
--
作者：
Niu, Hongyun;Zhao, Weijia;Cai, Yaqi
三聚氰胺-三聚氰酸（MA-CA）超分子被认为是制备管状或中空g-C3 N4的理想原料。由于MA-CA超分子的制备条件不同，g-C3 N4的形貌也不同，这不能用前驱体在煅烧过程中的自模板机制来解释。为了揭示由MA-CA衍生的g-C3 N4的形状变化的隐藏规则，我们使用机械化学技术制备了具有不确定形态的MA-CA混合物/超分子。聚合后，得到的g-C3 N4样品根据原料中CA和MA之间的氢键结合程度，分别为中空纳米棒（HNR）、纳米管（NT）和多孔纳米片（NS）。除g-C3 N4 NS外，其余样品的光催化活性均随比表面积的增大而增大。与中空和管状样品相比，g-C3 N4 NS的光催化性能相对较低，这可能是由于其CB位置较正，光生载流子分离能力较差。空心和管状g-C3 N4样品的空腔空隙实现了活性氧和有机污染物向局部微环境的富集，为促进污染物的氧化降解提供了驱动力。该研究为系统地调控g-C3 N4的形貌和物理化学性质提供了有力的依据。
The melamine-cyanuric acid (MA-CA) supramolecular is regarded as an ideal starting material to prepare tubular or hollow g-C3N4. The morphologies of g-C3N4 diversify owing to different preparation condition of MA-CA supramolecular, which is far from satisfactory to be explained by the mechanism of self-templating of precursors during calcination. To disclose the hidden rules of shape variety of g-C3N4 derived from MA-CA, we fabricate MA-CA mixture/supramoleculars with ill-defined morphologies using the mechanochemical technique. After polymerization, the obtained g-C3N4 samples are in the shapes of hollow nanorods (HNR), nanotubes (NT), and porous nanosheets (NS) depending on the hydrogen bonding degree between CA and MA in the starting materials. The photocatalytic activity of these g-C3N4 samples in H2 evolution and organic pollutants degradation increases with the rising of surface areas with the exception of g-C3N4 NS. The relatively lower photocatalytic performance of g-C3N4 NS than hollow and tubular g-C3N4 samples can be attributed to its more positive CB position and worse photogenerated carrier separation ability. The cavity void of hollow and tubular g-C3N4 samples realizes the enrichment of reactive oxygen species and organic pollutants into a local microenvironment, which provides a driving force to facilitate the oxidation degradation of pollutants. This study provides a forceful basis for the systematic fine-tuning of the morphologies and physico-chemical properties of g-C3N4.