Green synthesis of MnCo2O4 nanoparticles grown on 3D nickel foam as a self-supported electrode for oxygen evolution reaction

Abstract

The development of effective and low-cost catalysts for the oxygen evolution reaction (OER) has become an effective and promising strategy for sustainable energy technologies. In this work, we report a synthesis route for preparing MnCo2O4 nanoparticles on nickel foam (Ni foam) through a facile sol-gel method using Flaxseed (Linum usitatissimum) as a polymerizing agent and subsequent an adapted hydrothermal process. Here, a large surface area was obtained due to the small particle size combined with the absence of binders to promote the adhesion of the active material on the substrate. Thus, this seems to be an interesting strategy to boost electrocatalytic reactions. The structural, microstructural, and surface properties of MnCo2O4 electrodes are investigated by XRD, FESEM, TEM, FTIR, Raman, and XPS analysis. This electrode exhibits an overpotential of 296 mV (at 25 mA cm−2 current density), a Tafel slope of 82 mV dec−1, and excellent electrochemical stability for 15 h. This approach combines the features of a green synthesis with an adapted hydrothermal route to offer the advantages of a controllable reaction process, with good reproducibility, ally to uniform particle size distribution, short reaction time, and, mainly, respect for the environment. This demonstrates great potential in reproducing effective OER electrocatalysts for future applications.