One-step production of Pt–CeO2/N-CNTs electrocatalysts with high catalytic performance toward methanol oxidation

Abstract

Nitrogen-doped carbon nanotubes (N-CNTs) prepared by carbonization of polypyrrole nanotubes (PPy-NTs) are used as supports. Pt–CeO2/N-CNTs electrocatalysts are successfully prepared by in-situ growth of Pt and CeO2 nanoparticles (NPs) via a one-step coupling method of co-deposition and ethylene glycol reduction. Through structural characterization and electrochemical tests of the prepared electrocatalysts, the effects of preparation conditions on the structure of the electrocatalysts and their electrocatalytic activity for methanol oxidation were systematically investigated. The results verify that the Pt–CeO2/N-CNTs electrocatalysts were prepared using N-CNTs calcined at 700 °C as a support and 15 mM alkali concentration. They have the largest electrochemical active area and methanol oxidation mass activity of 85 m2 g−1(Pt) and 722 A g−1(Pt), respectively. Furthermore, the electrochemical stability and anti-CO poisoning performance of the electrocatalysts are significantly better than those of the commercial Pt/C electrocatalysts. The highly-dispersed Pt and CeO2 in Pt–CeO2/N-CNTs, a large number of N sites, and the synergistic action of Pt, CeO2, and N-CNTs result in a catalyst with excellent electrocatalytic activity, stability, and resistance to CO poisoning. The support structure and the dispersion of Pt and CeO2 can be controlled by changing the preparation conditions, which provides a basis for the industrial application of direct methanol fuel cells.