Carbon dots/polyoxometalate/Pt as a ternary composite for electrocatalytic methanol oxidation

Abstract

Development of high-efficiency anode electrocatalysts remains a challenge for direct methanol fuel cells (DMFCs). Herein, carbon dots (CDs) and Co-substituted sandwich polyoxometalate K₁₀[Co₄(H₂O)₂(PW₉O₃₄)₂]·20H₂O (Co-POM) were selected as building blocks to construct a new ternary composite electrocatalyst CDs/Co-POM/Pt for application in the methanol oxidation reaction. CDs/Co-POM/Pt was characterized by FTIR, high resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectrum (EDX), element mapping, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results revealed that a nanoflower-like Pt nanostructure with high dispersion and uniformity was formed. The electrochemical experiments showed that CDs and Co-POM enhanced the electrocatalytic ability of Pt, and the highest peak current density of 7.98 mA cm⁻² was obtained for CDs/Co-POM/Pt, corresponding to 3.6 times, 6.5 times and 10.8 times as high as that of CDs/Pt, Co-POM/Pt and pure Pt. Also CDs/Co-POM/Pt had good stability in the electrocatalytic process. This work paves a way for development of polyoxometalate-based electrocatalysts.

Keywords:

• Polyoxometalates
• carbon dots
• electrocatalysis
• methanol oxidation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Nos. 21601077 and 21573099), the Natural Science Foundation of Liaoning Province (20180550544), the Scientific research project of Liaoning Normal University (GD19L005) and the Opening Project of Key Laboratory of Polyoxometalate Science of Ministry of Education.