Urchin-like core-shell TiO2/α-MnO2 nanostructures as an active catalyst for rechargeable lithium-oxygen battery

Simple one-step synthesis of urchin-like Fe-Mn nanostructures via statistical design and their effects on the morphology

In the current investigation, a new urchin-like nanostructure using an authorized one-pot precipitation technique was synthesized using Taguchi statistical design. The effect of factors, including the concentration of FeSO4⋅7H2O, KMnO4, NaOH, and reaction temperature, on the diameter-to-length ratio of the nanoneedles and the regularity or irregularity morphology of other samples, was investigated. KMnO4 and FeSO4⋅7H2O, with a contribution of 32.62% and 30.9%, had the most substantial effect on the nanoneedles' diameter. The surface morphology and chemical composition of the as-prepared samples were studied using field emission scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy (EDX) analyses. The length and needle diameter was obtained 140 and 17 nm, respectively. The result of BET analysis for the highest and the lowest value of D/L shows that the smallest ratio of diameter to length has a high specific surface area. The results show that sample S4 has a particular surface area of 74 m2/g, much more than S3 (25 m2/g). The estimated crystallite size in synthesized S3 and S4 samples are 41.64 and 26.49 nm, respectively.