Introduction

Ruthenium oxide (RuO2), as the name denotes, is an oxide of Ruthenium. It is also referred to as ruthenium (IV) oxide, dioxoruthenium, ruthenium dioxide, ruthenia and ruthenium (IV) dioxide [1].

Properties

i.Highly insoluble [1]

ii.  Bears metallic conductivity [2]

iii. Stable at higher temperatures [1]

iv.    Has capacity to store charge in aqueous solutions ^[1,11] 

Preparation of RuO2

RuO2 can be obtained by oxidation of ruthenium trichloride containing water of crystallization (RuCl3.xH2O). Khorasani M. et al. advanced this elementary information by introducing NaOH and octanoic acid during the precipitation process. The addition of NaOH solution facilitates the formation of small RuO2 crystal nuclei at the preliminary stage of the reaction. Further addition of NaOH solution enhances the formation and development of RuO2 crystallites along one direction on the foundation of the initially formed RuO2 crystal nuclei. Afterwards, octanoic acid is added as a surfactant to refine the shape and size of RuO2 nanoparticles. Lastly, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) are introduced to determine the physical parameters of RuO2 nanoparticles (Fig. 1) ^[3]. 

Uses of RuO2

RuO2 is being used as a catalyst in the Stable Deacon Process for HCl oxidation. Sumitomo Chemicals developed this efficient and stable reaction route for catalyzing HCl oxidation over RuO2 supported on rutile TiO2 (Sumitomo process). The Sumitomo process is considered as a true breakthrough in the recovery of Cl2 from HCl and a big step towards sustainable chemistry^[4]