From Melamine-Cyanuric Acid Supramolecular Aggregates to Carbon Nitride Hollow Spheres
From Melamine-Cyanuric Acid Supramolecular Aggregates to Carbon Nitride Hollow Spheres
复制标题
DOI：
10.1002/adfm.201203732
复制
发表时间：
2013-08-07
影响因子：
19
通讯作者：
Thomas, Arne
中科院分区：
文献类型：
--
作者：
Jun, Young-Si;Lee, Eun Zoo;Thomas, Arne
石墨相氮化碳（g - CN）是一种很有前途的用于有机光合作用、太阳能转换以及污染物光降解的非均相无金属催化剂。通过纳米浇铸、掺杂和共聚来改变其结构、光学和电子性质，可轻易调节其催化性能。然而，同时优化尚未实现。在此，报道了一种利用三嗪分子间的分子协同组装简便合成介孔g - CN的方法。三聚氰胺氰尿酸复合物（MCA）的花状层状球形聚集体是由二甲基亚砜（DMSO）中的等分子混合物沉淀形成的。MCA在氮气氛围下于550℃热缩聚生成由基于三-s -三嗪的g - CN纳米片组成的介孔空心球（MCA - CN），其组成为C₃N₄.₁₄H₁.₉₈。源自MCA的层状结构诱导了更强的光吸收，使带隙拓宽了0.16 eV，并且使光激发载流子的寿命比块状g - CN的增加了一倍，而化学结构与块状g - CN相似。由于这些同时进行的改性，罗丹明B在催化剂表面的光降解动力学可提高10倍。
Graphitic carbon nitride (g-CN) is a promising heterogeneous metal-free catalyst for organic photosynthesis, solar energy conversion, and photodegradation of pollutants. Its catalytic performance is easily adjustable by modifying texture, optical, and electronic properties via nanocasting, doping, and copolymerization. However, simultaneous optimization has yet to be achieved. Here, a facile synthesis of mesoporous g-CN using molecular cooperative assembly between triazine molecules is reported. Flower-like, layered spherical aggregates of melamine cyanuric acid complex (MCA) are formed by precipitation from equimolecular mixtures in dimethyl sulfoxide (DMSO). Thermal polycondensation of MCA under nitrogen at 550 degrees C produces mesoporous hollow spheres comprised of tri-s -triazine based g-CN nanosheets (MCA-CN) with the composition of C3N4.14H1.98. The layered structure succeeded from MCA induces stronger optical absorption, widens the bandgap by 0.16 eV, and increases the lifetime of photoexcited charge carriers by twice compared to that of the bulk g-CN, while the chemical structure remains similar to that of the bulk g-CN. As a result of these simultaneous modifi cations, the photodegradation kinetics of rhodamine B on the catalyst surface can be improved by 10 times.