Platinum-modified cobalt nanosheets supported on three-dimensional carbon sponge as a high-performance catalyst for hydrogen peroxide electroreduction

• The Pt-Co NS@carbon sponge electrode shows unique nanosheet structure on the three-dimensional (3D) porous network skeleton with a large surface area.
• The Pt-Co NS@carbon sponge electrode achieves a reduction current density of −1.38 A cm−2 mg−1 in 3.0 mol L−1 KOH and 1.5 mol L−1 H2O2 at −0.50 V (vs. Ag/AgCl)
• The Pt-Co NS@carbon sponge electrode exhibits a desirable stability for the H2O2 electroreduction.

Pt-modified Co nanosheet@carbon sponge (Pt-Co NS@carbon sponge) electrode is synthesized via a facile sponge carbonization method coupled with a direct Co electrodeposition and Pt chemical-deposition. The obtained electrodes are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The catalytic performances of H2O2 electroreduction in alkaline medium are investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The Pt-Co NS@carbon sponge electrode exhibits unique nanosheet structure on the three-dimensional (3D) porous network skeleton with a large surface area and displays excellent catalytic performance. The Pt-Co NS@carbon sponge electrode achieves a reduction current density of −1.38 A cm−2 mg−1 in 3.0 mol L−1 KOH and 1.5 mol L−1 H2O2 at −0.50 V (vs. Ag/AgCl) accompanied with a desirable stability, which is significantly higher than the catalytic activity of H2O2 electroreduction achieved previously with precious metals as catalysts. The impressive electrocatalytic performance is largely attributed to the superior 3D open structure and high electronic conductivity, which ensures the full utilization of Pt surfaces and makes the electrode have higher electrochemical activity. Original Pt-Co NS@carbon sponge electordes have a great potential for the application in fuel cells due to its facile preparation, high performance and low cost.

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