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.