Technological Features of Creating Hole Structures on the Base of MoS₂ and the Electrochemical Behavior of MXene/Holey MoS₂ Hybrids in Oxygen Reduction Reactions

High-performance noble metal-free two-dimensional (2D) electrochemical catalysts have gained great importance to replace the Pt-based catalysts in oxygen reduction reactions (ORR) to reduce not only the cost of the fuel cells but also enhance the energy efficiency. Herein, we designed a novel ORR catalyst by forming MXene/holey MoS₂ hybrids. The holes were created on the basal plane of MoS₂ both to create electroactive defective regions and enhance the diffusion of the reactants in the catalyst layer. Holey 2D MoS₂ layers were characterized using transmission electron microscopy (TEM), UV-ViS spectroscopy, scanning electron microscope (SEM), and Raman spectroscopy. The TEM images indicated the formation of nano-holes on the basal plane of MoS₂. The increased defect concentration was revealed from the Raman spectra of the samples. The successful synthesis of the V₂C MXene layers was confirmed using SEM and EDS results. The holes created on the basal plane of 2D MoS₂ boosted the electrochemical ORR performance compared to the pristine 2D counterparts, which is attributed to the defect-rich active sites on the edge of the holes and enhanced diffusion of the reactants. In conclusion, our designed MXene/holey MoS₂ hybrid catalyst exhibits superior electrochemical performance in ORR, offering a promising approach for the development of cost-effective and efficient catalysts for fuel cell applications.