Reduced graphene oxide supported chromium oxide hybrid as high efficient catalyst for oxygen reduction reaction

• Cr2O3, which is usually adopted as ceramic material, is doped as catalyst for oxygen reduction.
• Transitional metal oxide with low cost and rich sources is employed as catalysts for oxygen reduction.
• 4-electron style oxygen reduction reaction is observed with the catalysis of Cr2O3.

Reduced graphene oxide (rGO) supported nano-chromium oxide (Cr2O3/rGO) catalyst for oxygen reduction reaction (ORR) has been successfully synthesized by the pyrolysis of chromium-urea coordination compound. The structure and morphology of the hybrid are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) tests. XRD tests reveal that the Cr2O3 with hexagonal structure is obtained. SEM and TEM tests show that the nano-Cr2O3 is supported by rGO sheet. The cyclic voltammetry, tafel, linear scanning voltammetry and current-time chronoamperometric tests prove that the obtained Cr2O3/rGO hybrid has a remarkable catalytic activity and good stability for oxygen reduction. Both the rotating disc electrode and rotating ring disc electrode tests approve that the ORR major happens through 4-electron reaction style. The Cr2O3/rGO hybrid is a promising low cost and high performances catalyst for ORR of alkaline electrolyte.