Facile cubic Nd doped MnO nanostructure synthesis as effective electrocatalyst for oxygen evolution reaction

Abstract

Development of an effective electrocatalyst for the electrochemical water splitting to store electrical energy as H₂ fuel and improve sluggish oxygen evolution reaction (OER) is the need of the time. For H₂ production and making it more accessible, developing a low-cost fabrication method for an efficient OER catalyst with characteristics including a large surface area, an abundance of active sites, and exceptional stability is necessary. In this study, neodymium-doped manganese oxide (Nd-MnO) with a larger specific surface area (32.6 m²/g), small size particles (84 nm), and most crucially high concentration of oxygen vacancies fabricated via a simple solution reduction method using NaBH₄ as a reductant. Nd-MnO has an overpotential of 394 mV and a Tafel slope value of 84 mV/dec reaching 10 mA/cm², superior to RuO₂ and MnO. The potential results of the Nd-MnO are due to a unique structure consisting of nanocubes that may enhance OH ion mass diffusion/transport and offer a large number of active sites for catalysis of OER, as well as oxygen vacancies which are also validated by DFT that may enhance the electronic conductivity and provide H₂O adsorption on the surface of neighboring Mn³⁺ sites.