Interface modulation of Mo2C@foam nickel via MoS2 quantum dots for the electrochemical oxygen evolution reaction

Abstract

It is highly desirable and challenging to develop active, inexpensive and available catalysts for the oxygen evolution reaction (OER). Herein, we proposed a simple strategy to anchor MoS₂ quantum dots (QDs) on the Mo facet in Mo₂C@foam nickel to craft an atomic-level heterostructure (MoS₂ QDs@Mo₂C@NF). The MoS₂ QDs confined in Mo₂C established a significant link between the electronic manipulation and activities of Mo₂C by combining experiments and first-principles calculations. The Mo facet in Mo₂C acting as an electron catcher could accelerate the vertical transmission of electrons from MoS₂ QDs to Mo₂C and enrich electrons onto the Mo facet. Meanwhile, electrons on Mo₂C by electro-excitation could quickly migrate to MoS₂ QDs through the intimate Mo (Mo₂C)–S bond interfaces, resulting in a highly effective interface with low edge contact resistance. The as-synthesized MoS₂ QDs@Mo₂C@NF exhibited considerable catalytic activity for the OER in 1 M KOH solution with an overpotential of 1.34 V at 10 mA cm⁻² and Tafel slope of 57 mV dec⁻¹ in comparison to RuO₂@NF (1.35 V and 41 mV dec⁻¹) owing to optimal adsorption energies of the OER intermediates on the MoS₂ QDs@Mo₂C@NF, which originated from a strong electronic coupling effect at the heterointerfaces. These results herald the interface modulation of the electrocatalysts in the presence of a support carrier providing a promising strategy for designing advanced electrocatalysts.