Investigation of electrocatalytic properties of MnO۲-ZnO/rGO aerogelnanocomposite

In recent decades, environmental concerns and the global energy crisis caused by thereduction of fossil fuels have led to an intensive search for clean and renewable energy sources,especially through electrocatalytic processes. On the other hand, the morphology and structure ofthe manufactured electrocatalysts can have useful features for better catalytic performance [۱][۲].Therefore, the design and synthesis of innovative high-performance nanocomposites in theelectrochemical processes, such as the oxygen evolution reaction (OER) and hydrogen evolutionreaction (HER), is very important and has attracted a lot of attention in recent years [۳][۴]. In thisstudy, the novel MnO۲-ZnO/rGO aerogel nanocomposite was synthesised to consider the OERand HER studies. The synthesized rGO aerogel, MnO۲ and ZnO nanoparticles, MnO۲/rGOaerogel and ZnO/rGO aerogel binary nanocomposites, and MnO۲-ZnO/rGO aerogel ternarynanocomposite have been characterized by using X-ray powder diffraction (XRD), Fouriertransform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM)coupling with energy dispersive spectroscopy (EDS), Brunauer-Emmett-Teller (BET) theory toinvestigate the structure, functional groups, morphology with elemental distribution, and specificsurface area of materials, respectively. The obtained results of FE-SEM and XRD revealed thatthe graphene aerogel has incorporated nanoparticles of MnO۲ and ZnO in the form of a substratewith high porosity and large pore size, without collapsing the surface structure. In addition,cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetryhave been employed to consider the electrochemical behaviors of synthesized samples. Theelectrochemical results show that MnO۲-ZnO/rGO only shows lower OER activity thanMnO۲/rGO, but in terms of HER, it has good electrocatalytic activity compared to the restprepared samples.

Keywords:

MnO۲-ZnO/rGO , aerogel , HER , OER