Highly Active MoS₂-MXenes Hybrid Electrocatalysts Towards the Oxygen Reduction Reaction

In this work, catalytic performance of MoS2 supported on Mo2TiC2 and Ti3C2 MXenes towards the oxygen reduction reaction (ORR) was studied. These materials were synthesised through an etching route of MAX phases as precursors of MXenes, followed by a hydrothermal treatment to coat them with MoS2. This procedure generated MoS2 nanospheres covering the MXenes, which were verified by SEM-EDX mapping, Raman spectroscopy and XPS. Activity of these materials towards ORR was studied by RRDE, comparing its performance with that of individual MoS2 and MXenes. As main features, it was demonstrated that production of HOO- occurring on the composites decreases in comparison with individual materials. Long-term stability tests performed in O-2-saturated electrolyte showed a drop in the activity of the materials due to the increase in the production of HOO-, although no morphological or compositional changes were observed. Despite this result, the improvement of the catalytic properties of the individual materials means that these composites can be considered as candidates to be used as supports of active non-noble metal nanoparticles in the cathodes of anion exchange membrane fuel cells (AEMFCs).