CoOx-CoP/Nitrogen-Doped Tubular-Carbon Nanostructures Supported over Ceria Nanorods as an Efficient Scavenger in the Electrocatalytic Oxygen Reduction Reaction

The development of electrocatalysts to eliminate oxygenated radicals produced during the incomplete oxygen reduction reaction (ORR) and increase the practical durability of the proton exchange membrane fuel cell (PEMFC) and alkaline membrane fuel cell (AMFC) is a hot topic of research. Herein, we report cobalt oxide (CoOx) and cobalt phosphide (CoP)-encapsulated nitrogen-doped tubular carbon (NC) supported over ceria nanorods (CeO2) as an efficient and durable catalyst for an electrocatalytic ORR. The synthesized material (CoOx-CoP/NC@CeO(2)2) delivers outstanding results when employed as an electrocatalyst to reduce oxygen molecules. Comparable activity to 20 wt % Pt/C is demonstrated by the CoOx-CoP/NC@CeO(2)2 in terms of the half-wave (E-1/2 approximate to 0.85 V-RHE) and onset potential (E-onset approximate to 0.98 V-RHE) in 0.1 M KOH. For comparison, CoOx-CoP/NC2 is synthesized to determine the effect of CeO2 during the electrocatalytic ORR process. The as-synthesized final material, that is, CoOx-CoP/NC@CeO(2)2 demonstrates excellent durability over a period of 30 h with a retention of 99.9% current density in comparison to CoOx-CoP/NC2 (95.3%). The enhanced durability of CoOx-CoP/NC@CeO(2)2 is attributed to the porous structure of CeO2, which captures the harmful radicals produced during the reaction. The decrease in the absorbance of the model radical with the increase in the concentration of CoOx-CoP/NC@CeO(2)2 determined from UV-visible spectroscopy in this work reveals the scavenging ability of the synthesized material.