Síntese, microestrutura e caracterização eletroquímica de compostos a base de níquel e cobalto para reação de evolução de oxigênio.

Abstract

This work presents the development of new oxide electrocatalysts based on Ni and Co for the Oxygen Evolution Reaction, as well as the search for sustainable alternatives in the production of nanoparticle materials, considering the growing demand for renewable energy. Therefore,

here, the synthesis and microstructural/electrochemical characterization of Nickel and Cobalt- based nanoparticles, employing the proteic sol-gel method, with Agar-Agar as polymerizing

agent was studied. Microstructural analysis was performed using X-ray diffraction techniques (including Rietveld refinement), Scanning Electron Microscopy, Fourier transform infrared spectroscopy and Raman Spectroscopy. The electrochemical performance of the synthesized compounds was evaluated using linear scanning voltammetry, cyclic voltammetry, and Electrochemical impedance spectroscopy. Electrochemical analyzes indicate an improvement in electrocatalytic performance, especially when the cobalt content is increased, thus favoring the Oxygen Evolution Reaction process. In fact, (Ni,Co)O-Co3O4 shows a low overpotential of 356 mV vs. RHE at J = 10 mA cm-2 and a TOF of 0.009978 mol O2 s-1 at just 500 mV vs. RHE. Furthermore, the prepared nanoparticles present excellent chemical stability, revealed by chronopotentiometric analysis over 15 h.