Effect of transition metals on the electrocatalytic activity of N-doped carbon composites derived from polydopamine for oxygen evolution and oxygen reduction reactions

Abstract

In recent years, renewable energies have played an essential role in the technological development to meet energy demand and replace fossil fuels. At the same time, new challenges have arisen in order to implement clean energy production. The problem to store renewable energy that is obtained intermittently in the long term has led the development of fuel cells, electrolyzers and unitized regenerative fuel cells (URFC) to use hydrogen as an energy vector. URFCs can be used for both electric power production and hydrogen generation by adapting to the energy needs of the power grid. The most recent studies using an anion exchange membrane as electrolyte have opened up a range of possibilities for synthesizing new catalysts by replacing noble metals such as Pt, Ir or Ru with cheaper transition metals in combination with N-doped carbon structures [1] This work focuses on the development of noble metal-free bifunctional electrocatalysts for the oxygen electrode of unitized regenerative alkaline fuel cell (UR-AFC), where oxygen evolution (OER) and reduction (ORR) reactions take place [2]. Composites based on non-precious metals such as Ti, Mn, Fe, Co, Ni or Zn, and nitrogen-doped carbonaceous nanostructures obtained from polydopamine have been prepared.