Micro Flower-Like Hierarchical Mo₂C/Co@NC (N-Doped Carbon) for Efficient Bifunctional Electrocatalyst

The development of low-cost and high-efficiency electrocatalysts for the water-splitting reaction to produce oxygen and hydrogen from alkaline electrolytes remains a major challenge, especially from the perspective of realizing fast and efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalysts, and it is important to improve the performance of these reactions through rational catalyst design. In this study, Co-based heterostructures composed of cobalt (Co) and molybdenum carbide (Mo₂C) nanoparticles with micro-flower-like structures were intentionally designed as precursors for OER and HER electrocatalysts. In particular, during polymerization, nanoparticle (metal precursor) ions and dopamine aggregates combined to grow into nano-flakes and retained their structure after carbonization, forming micro-flower-like structures characterized by high specific surface area and porosity. The catalysts with hierarchical heterostructures constructed using this unique structure showed activities similar to those of the commercially available IrO₂ and Pt/C catalysts, reaching current densities of 10 mA/cm² for OER and HER in 0.1 M KOH and exhibiting good durability. Therefore, our results present new concepts for the structuring and fabricating catalysts to realize efficient OER and HER kinetics, and we expect that they will be utilized in the energy conversion field.