Generalized synthesis and evaluation of formation mechanism of metal oxide/sulphide@C hollow spheres

Abstract

Herein, we report a generalized novel soft-template approach for the synthesis of a variety of uniform metal oxide (MoO₂, Fe₃O₄, V₂O₃) and sulphide (MoS₂, ZnS)@C hollow spheres using sucrose and cetyl trimethylammonium bromide (CTAB) as a soft template. The synthesized hollow spheres are uniform in size, with a size range of 800 nm to 1.3 μm. The developed methodology allows for altering the carbon content by just varying the amount of sucrose in the precursor solution. The formation mechanism of the soft template was also studied by using isothermal titration calorimetry (ITC), infrared (IR) spectroscopic analysis and scanning electron microscopy (SEM) of the intermediate. The strategy was developed based on the in situ formation of the spherical soft template by the interaction of sucrose and CTAB under the experimental conditions, formation of an inorganic shell by the interaction of a metal salt and template surface, carbonization of sucrose under hydrothermal conditions, and finally formation of the desired metal oxide/sulphide@C through calcination under 5% H₂ in a flow of N₂. Using the synthesized MoS₂@C hollow sphere as a typical representative of such hollow spheres, its performance was examined as an anode for a lithium-ion battery to determine the applicability of the developed procedure; it exhibited a high specific capacity (∼1100 mA h g⁻¹ at 150 mA g⁻¹) as a lithium-ion battery (LiB) anode.