Simple self-organization-based synthesis of gold nanoparticle-implanted ZnO aerogels with good sensing performance to gaseous ethanol

Simple fabrication of metal-modified oxide aerogels is expected but remains challenging. This work presents a sample one-pot synthesis method for gold nanoparticle (NP) implanted ZnO (Au-ZnO) aerogels just by sequentially adding (CH3COO)2Zn and NaBH4solutions into a pre-prepared Au colloidal solution. The typically fabricated Au-ZnO aerogels are constituted by ZnO networks implanted with uniform Au NPs. The Au NPs had a size of about 100 nm, and the ZnO nanochains in the networks were about 10 nm in thickness. Further, the proportion of the Au NPs in the final aerogels could be tuned by using different amounts of the Zn precursors. Furthermore, a mechanism based on metal oxidation and oriented connection growth (a self-organization process) has been presented for describing the formation of such Au-ZnO aerogels. In the typical formation, the Zn2+ions first convert into ZnO beads, and then are self-organized to form networks wrapping the colloidal Au NPs under the effect of linker molecules, and this matches well with the observed experimental results. Most importantly, these Au-ZnO aerogels show great structurally enhanced gas sensing properties to gaseous ethanol compared with a pure ZnO film. They have a fast response (about 30 s), a high selectivity, and quantitative sensing to the target gas. This work has provided a simple preparation method for Au-ZnO aerogels, and also shows their great potential in gas sensing applications.