Abstract
Flower-like NiO hierarchical structures with 2–5 μm diameter assembled from nanosheet building blocks have been successfully fabricated via a wet-chemical method combined with thermodecomposition technology. The template-free method is facile and effective in preparing flower-like NiO superstructures in high yield. The intermediate product and final hierarchical structures are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform IR (FTIR), and thermogravimetric analysis (TGA). The effects of growth temperature and reaction time on the morphologies of the as-prepared structures were investigated by SEM characterization and a possible mechanism for the formation of flower-like NiO is proposed. Based on the nitrogen adsorption and desorption measurements, the BET surface area of the as-obtained sample is 55.7 m2/g and the pore-size distribution plot indicates a bimodal mesopore distribution, with pore sizes of ca. 2.6 nm and 7.4 nm, respectively. In comparison with sphere-like and rod-like structures, the flower-like NiO hierarchical structures show an excellent ability to rapidly remove various pollutants when used as adsorbent and photocatalyst in waste-water treatment, which may be attributed to its unique hierarchical and porous surface structures.
Highlights
Nanoscale materials have been pursued extensively due to their unique physical and chemical properties and promising applications in nano-devices compared to those of their bulk counterparts [1,2].The morphology, crystallography and size of the nano-structured materials can greatly influence their optical, electronic, magnetic, and catalytic properties [3,4,5,6]
Based on the experimental results, we find that the reaction temperature plays a crucial role in the formation of flower-like hierarchical structures
At the reaction time of 3 h, the nanosheets with unchanged thickness gradually develop in size and further interweave together, and form the preliminary flower-like hierarchical structures, that is the aggregation of flower-like structures (Figure 4e,f)
Summary
Nanoscale materials have been pursued extensively due to their unique physical and chemical properties and promising applications in nano-devices compared to those of their bulk counterparts [1,2]. Controlled organization of primary building units with various dimensions into ordered superstructures has been another focus of significant interest for material chemistry and device fabrication [7,8,9,10]. Such a capability is attractive in understanding the concept of self-assembly of original building blocks, and due to the importance in its potential applications [11]. Developing a facile and template-free method to prepare hierarchical NiO structures is of scientific and practical importance. NiO samples on various pollutants indicates its potential application in water treatment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
