Nickel foam/reduced graphene oxide/CoNi2S4-MoO2 nanosheets with a core–shell structure formed: An efficient electrocatalyst for the hydrogen evolution reaction

Abstract

The performance of single-component hydrogen evolution reaction (HER) electrocatalysts in terms of physicochemical properties and electrocatalytic efficiency has shown limitations for large-scale industrial applications. Consequently, developing new HER electrocatalysts with superior performance and mature technology is crucial for advancing this field. In this study, nickel foam/reduced graphene oxide/CoNi2S4-MoO2 (NF/rGO/CoNi2S4-MoO2) was prepared using a combination of water bath and two-step hydrothermal methods. Reduced graphene oxide (rGO) enhances the catalyst’s conductivity and induces uniform distribution of CoNi2S4. The sheet-like CoNi2S4 provides numerous active sites for the vertically distributed MoO2 nanosheets, reducing agglomeration and ensuring even distribution on the surface. The synergistic effect among rGO, CoNi2S4, and MoO2, along with their unique structures, facilitates charge transfer, enhancing the material’s electrochemical hydrogen evolution capabilities even more. The synthesized NF/rGO/CoNi2S4-MoO2 nanosheets exhibited excellent electrocatalytic performance. The overpotential of NF/rGO/CoNi2S4-MoO2 was as low as 65 mV in a 1.0 M KOH solution at a current density of 10 mA·cm−2, and the Tafel slope was 96.48 mV·dec−1.

Keywords

• Core–shell structure
• Transition metal catalysis
• RGO
• Stability