Covalently functionalized layered MoS₂ supported Pd nanoparticles as highly active oxygen reduction electrocatalysts

Abstract

Molybdenum disulfide nanosheets covalently modified with a 1,2-dithiolane derivative were used as novel substrate for the immobilization of Pd nanoparticles (PdNPs) towards the development of highly efficient hybrid electrocatalyst, namely...

Oxygen Reduction Reaction Promoted by the Strong Coupling of MoS2 and SnS

“…For MoS 2 , good chemical and electrochemical stability with E 1 2g and A 1g modes can be observed at about 383 and 407 cm −1 throughout the potential range, respectively. 17 The intensity of these two MoS 2 peaks weakens when the potential decreases from 0.914 to 0.814 V and strengthens again with decreasing potential, suggesting relatively weak interactions with oxygen intermediates and good chemical and electrochemical stability. That is, MoS 2 can promote the removal of oxygen-containing intermediates.…”

“…Figure a shows the in situ full spectra of MoS 2 -SnS/NPC at different potentials. SnS, S vacancy, MoS 2 , and carbon characteristic peaks can be detected at about 151, 275, 400, and 1388/1600 cm –1 , respectively . The presence of the S vacancy is the result of an electrocatalytic ORR process, which promoted the formation of more Mo-edge active sites for oxygen adsorption.…”

“…After polarization under a low potential of <0.564 V, the Sn ion received an electron and interacted with S, forming high-crystalline SnS. For MoS 2 , good chemical and electrochemical stability with E 1 2g and A 1g modes can be observed at about 383 and 407 cm –1 throughout the potential range, respectively . The intensity of these two MoS 2 peaks weakens when the potential decreases from 0.914 to 0.814 V and strengthens again with decreasing potential, suggesting relatively weak interactions with oxygen intermediates and good chemical and electrochemical stability.…”

“…SnS, S vacancy, MoS 2 , and carbon characteristic peaks can be detected at about 151, 275, 400, and 1388/1600 cm −1 , respectively. 17 The presence of the S vacancy is the result of an electrocatalytic ORR process, which promoted the formation of more Mo-edge active sites for oxygen adsorption. For the enlarged Raman spectra shown in Figure 5b, no obvious SnS peak can be seen in the polarization potential range of 0.614−1.114 V, and a SnS peak with an increased intensity appeared when the potential was decreased to 0.564 V. This change can be due to the fact that the surface SnS is unstable in O 2 -saturated alkaline electrolytes near the onset potential, 27 leading to the formation of a Sn ion.…”

“…Doping heterogeneous atoms and combining with a conductive substrate are feasible strategies to promote the ORR catalytic activity of MoS 2 . For example, by decorating MoS 2 with Fe and Ag, Nguyen et al exhibited an enhanced ORR activity due to the introduction of additional active sites. − Moreover, MoS 2 -based heterostructures with an adjustable composition can integrate the advantages of different components, holding great potential in tuning the ORR activity. , Li et al reported that when MoS 2 was integrated with Co 9 S 8 , the ORR activity of the obtained Co 9 S 8 @Co 9 S 8 @MoS 2 -0.5 heterostructure (with a half-potential of 0.776 V) was obviously boosted benefiting from the strong interface effect between MoS 2 and Co 9 S 8 . For a heterostructure catalyst, the formed interfaces between two components may display unique electronic features, also known as interfacial effects, which cannot be achieved in a single component. − Two components with different oxygen affinities and geometrical structures will induce electronic rearrangement and electronic, coordination, geometric, and synergistic effects, benefiting the adsorption, activation, and desorption of oxygen-containing substances .…”