Novel ultralong hollow hyperbranched Cu2-xSe with nanosheets hierarchical structure: Preparation, formation mechanism and properties

Cubic phase of novel hollow hyperbranched Cu2-xSe with nanosheets hierarchical structure was prepared on a Cu foil substrate by a facile solution route, using CuO nanosheets film as a precursor, and its formation mechanism was explored. The optical, gas sensing and superparamagnetic properties of the hollow hyperbranched Cu2-xSe were studied. The results show that the hollow hyperbranched Cu2-xSe microstructure could grow as long as 118 mu m with diameters of 2-4 mu m. Each hyperbranched Cu2-xSe contains four orthogonally located side branches and each side branch is composed of four orthogonal sub-branches which are assembled by numerous parallelly located nanosheets. The hollow hyperbranched Cu2-xSe microstructures were formed through the transformation reactions from CuO nanosheets to Cu2-xSe nanosheets, where the CuO nanosheets function as the sacrificing template, followed by multilevel oriented self-assembly. We found that the ultralong hollow hyperbranched Cu2-xSe microstructures possess extraordinary superparamagnetic property at room temperature. Besides, the Cu2-xSe product displays strong UV-visible light-harvesting ability and excellent gas sensing property to ammonia gas. (C) 2019 Elsevier B.V. All rights reserved.