Effect of Co-Fe alloy nanoparticles on the surface electronic structure of molybdenum disulfide nanosheets and its application as a bifunctional catalyst for rechargeable zinc air battery

Abstract

It is of great significance to improve the performance of electrocatalysts by constructing suitable heterogeneous interfaces to adjust the electronic structure of their surfaces. Here, we design and synthesize Co-Fe alloy nanoparticles (NPs) modified nitrogen-doped cubic carbon box (NC) supported MoS 2 nanosheets (NC@MoS 2 @Co-Fe) as a bi-functional electrocatalytic electrode material, which possesses excellent electrocatalytic oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance. The NC@MoS 2 @Co-Fe exhibits remarkable bifunctional electrocatalytic activities with an ORR half-wave potential of 0.73 V in 0.1 M KOH electrolyte and an OER overpotential of 400 mV, driving a current density of 10 mA cm −2 . The advanced catalytic performance can be attributed to the unique heterojunction structure of the catalyst. The size of the Co-Fe alloy NPs supported on MoS 2 can be tuned to avoid the excessive growth of alloy NPs and to expose more catalytic active sites. Meanwhile, the loaded Co-Fe alloy NPs should be covered with a calcined carbon layer derived from the organic ligand to prevent oxidation passivation and particle aggregation. The structure formed by Co-Fe alloy NPs and NC@MoS 2 optimizes the electronic structure of the active center and accelerates the electrocatalytic reaction rate, thus synergistically improving the bi-functional electrocatalytic activity of the NC@MoS 2 @Co-Fe catalyst and can be applied to rechargeable zinc air batteries. Co-Fe alloy nanoparticles (NPs) modified nitrogen-doped cubic carbon box (NC) supported MoS 2 nanosheets (NC@MoS 2 @Co-Fe) is synthesized as a bi-functional electrocatalytic electrode material, which possesses excellent electrocatalytic oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance. • The NC@MoS 2 @Co-Fe exhibits remarkable bi-functional electrocatalytic activities. • The assembled Zn-air batterie delivers a high power density and superior cycling performance. • The precise control of Co-Fe alloy on the surface electronic structure is realized. • The hollow nitrogen doped carbon box has a good electrolyte diffusion channel. • The unique MoS 2 @Co-Fe heterojunction structure optimizes the electronic structure of the active center.