Feng Wei, Wang Yaming, Chen Junchen, Guo Lixin, Ouyang Jiahu, Jia Dechang, Zhou Yu
Institute for Advanced Ceramics, Harbin Institute of Technology, No. 92 Xidazhi Street, Harbin, Heilongjiang Province, P. R. China.
Phys Chem Chem Phys. 2017 Jun 7;19(22):14596-14605. doi: 10.1039/c7cp02039b.
This study constructs a unique structure of reduced graphene oxide (RGO)/ZnO composite combining starlike ZnO with RGO doped by ZnO nanocrystals through an in situ crystallization method. After mixing graphene oxide (GO) dispersion with Zn(NO) and KOH solution, zinc ions absorbed on graphene oxide sheets transform ZnO nanocrystals, and the free zinc ions form starlike ZnO. After thermal treatment, RGO sheets doped by uniformly dispersed ZnO nanocrystals wrap the starlike ZnO or insert in the gap between them. Composites of different mass ratio of RGO to ZnO (9 : 1, 8 : 1, 5.5 : 1, and 2 : 1) have been achieved by modulating the quantity of Zn(NO) and KOH. The dielectric and microwave absorption properties of the composites show dependence on the mass ratio of RGO to ZnO. The sample with the mass ratio of 8 : 1 shows the most prominent microwave absorption properties, with strong absorption (minimum reflection loss of -77.5 dB) and broad effective absorption bandwidth (6.9 GHz). The enhanced microwave absorption properties can be ascribed to the starlike ZnO, which hinder the agglomeration of RGO, as well as the ZnO nanocrystals, effectively improving the interface of the heterostructure and the impedance matching of RGO.
本研究通过原位结晶法构建了一种独特结构的还原氧化石墨烯（RGO）/ZnO复合材料，该复合材料将星形ZnO与由ZnO纳米晶体掺杂的RGO相结合。将氧化石墨烯（GO）分散液与Zn(NO)和KOH溶液混合后，吸附在氧化石墨烯片上的锌离子转化为ZnO纳米晶体，游离的锌离子形成星形ZnO。经过热处理后，由均匀分散的ZnO纳米晶体掺杂的RGO片包裹星形ZnO或插入它们之间的间隙。通过调节Zn(NO)和KOH的用量，制备了不同RGO与ZnO质量比（9 : 1、8 : 1、5.5 : 1和2 : 1）的复合材料。复合材料的介电和微波吸收性能表现出对RGO与ZnO质量比的依赖性。质量比为8 : 1的样品表现出最突出的微波吸收性能，具有强吸收（最小反射损耗为-77.5 dB）和宽有效吸收带宽（6.9 GHz）。增强的微波吸收性能可归因于星形ZnO，它阻碍了RGO的团聚，以及ZnO纳米晶体，有效地改善了异质结构的界面和RGO的阻抗匹配。
