MnCo2O4 nanoparticles supported on nitrogen and sulfur co-doped mesoporous carbon spheres as efficient electrocatalysts for oxygen catalytic reactions

Abstract

The development of efficient bifunctional electrocatalysts for the oxygen reduction and oxygen evolution reactions is essential to address the challenge of sluggish reaction kinetics. MnCo₂O₄ nanoparticles supported on nitrogen and sulfur co-doped mesoporous carbon spheres are prepared as non-precious metal electrocatalysts by pyrolysis of thiourea and hydrothermal treatment. The co-doping of nitrogen and sulfur from thiourea into the carbon spheres plays an important role in bimetallic covalent coupling with manganese and cobalt oxides. The as-prepared catalysts exhibit promising catalytic performance of the oxygen reduction reaction compared to commercial platinum catalysts due to the existence of highly active sites. Remarkably, the as-prepared catalysts also exhibit promising catalytic activity of the oxygen evolution reaction, comparable to that of commercial ruthenium oxide in terms of the onset potentials and Tafel slope, and show better durability for both the oxygen reduction reaction and oxygen evolution reaction in an alkaline solution.