Polymetallic sulfide assembly of Cu2S/Ni3S2 grown in situ on Ni foam as a self-supported electrode and electrocatalyst for high-efficiency non-enzymatic glucose sensing

Abstract

A polymetallic sulfide of Cu₂S/Ni₃S₂ is assembled in situ on nickel foam (NF), serving as a self-supported electrode and electrocatalyst for non-enzymatic glucose sensing. Benefiting from interfacial synergistic effects, the Cu₂S/Ni₃S₂/NF composite exhibits outstanding electrocatalytic capability toward glucose oxidation, with a high sensitivity of 22 750 µA mM⁻¹ cm⁻², a low limit of detection (LOD) of 0.51 µM, a broad linear detection range of 1 µM–1 mM, and good selectivity against interfering species. Density functional theory (DFT) calculations of the Cu₂S/Ni₃S₂ heterojunction are performed to reveal the density of states (DOS) and charge density difference. Effective interfacial electron transfer between Cu₂S and Ni₃S₂ modulates the electronic structure, thereby enhancing electrocatalytic activity. The optimal d-band centers (d_bc) of Cu and Ni in Cu₂S/Ni₃S₂ are beneficial for the promotion of glucose sensing sensitivity. This work provides an efficient strategy for fabricating polymetallic sulfides for application in next-generation non-enzymatic glucose sensing.