A novel composite of W18O49 nanorods on reduced graphene oxide sheets based on in situ synthesis and catalytic performance for oxygen reduction reaction

Abstract

A novel composite catalyst based on in situ synthesis of W₁₊₄₉ nanorods on reduced graphene oxide sheets was successfully fabricated through a one-pot solvothermal route. The as-prepared W₁₈O₄₉–reduced graphene oxide (rGO) composite has been systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman microscopy, X-ray photoelectron spectra, and a rotating disk electrode. Compared to W₁₈O₄₉ nanorods or reduced graphene oxide alone, or their physical mixture, the composite catalyst exhibited unexpectedly high ORR activity with a more positive onset-potential (close to that of Pt/C) and a higher kinetic current density (J_K), which is mainly attributed to the nanorod morphology, surface oxygen vacancies of W₁₈O₄₉, and strong coupling interaction between the W₁₈O₄₉ nanorods and reduced graphene oxide sheets. These results raise the possibility of developing low-cost and efficient ORR electrocatalysts.