Synthesis and characterization of oxidized CoMnAl-layered double hydroxide and graphene oxide nanocomposite as a more efficient electrocatalyst for oxygen evolution reaction

In the present work, a nanocomposite of oxidized CoMnAl-layered double hydroxide (LDH) and graphene oxide (GO) was prepared by using the coprecipitation method. The obtained nanocomposite was characterized by X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) methods to get information about the structure, composition and morphology. After physicochemical characterization of the prepared sample, it was applied as an electro catalyst for the oxygen evolution reaction (OER). The obtained results show that the oxidized nanocomposite modified glassy carbon electrode exhibited higher electrocatalytic activity (with onset over potential of approximate to 0.3 V in 0.1 M KOH and a Tafel slope of 36 mV dec(-1)) and excellent stability than that of the non-oxidized nanocomposite. On the other hand, in order to enhance the oxygen evolution reaction efficiency and achieve a higher electrocatalytic activity of the nanocomposite, the existence of higher oxidation numbers for the metal cations in LDH structure is indispensable. For this purpose, we utilized H2O2 as the oxidant agent to achieve the higher oxidation numbers of the LDH cations (Co3+, Mn4+).