Investigating the effect of CeO2 on the radical scavenging activity of Pt@CoOx/NC@CeO2 during the electrocatalytic oxygen reduction reaction in acidic and alkaline environments

Abstract

Researchers have concentrated on developing electrocatalysts that are especially designed to minimise oxygenated radicals generated in partial oxygen reduction reactions (ORRs). Herein, we report Pt@CoO_x/NC@CeO₂1 as a cost-effective, stable, and highly durable electrocatalyst in both 0.1 M KOH and 0.1 M HClO₄ electrocatalytic environments with low platinum loading (ca. 5% only). Outstanding results are delivered by the Pt@CoO_x/NC@CeO₂1 with half-wave potential (E_1/2) ∼ 0.89 V_RHE in 0.1 M KOH. The optimized electrocatalyst, i.e., Pt@CoO_x/NC@CeO₂1, is also found to be efficient for the ORR in 0.1 M HClO₄ with E_1/2 ∼ 0.89 V_RHE compared to 20 wt% Pt/C. The innovative support (CoO_x/NC) obtained through facile calcination of ZIF-12 has been deposited over porous ceria nanorods (CeO₂). The platinum nanoparticles are then decorated over CoO_x/NC@CeO₂. To investigate the influence of cobalt on the electrocatalytic ORR process, platinum-decorated commercial multiwalled carbon nanotubes (Pt@MWCNTs1) were synthesized using the same synthetic methodology. The as-synthesized electrocatalyst (Pt@CoO_x/NC@CeO₂1) demonstrates enhanced mass activity (MA) of ∼263 mA mg_Pt⁻¹ in 0.1 M KOH and 231 mA mg_Pt⁻¹ in 0.1 M HClO₄ at their E_1/2 and an enhanced electrochemical active surface area (ECSA) of ∼261 m² g⁻¹. The material also demonstrates radical scavenging activity resulting in enhanced durability with a significant amount of current retention for 30 h in both alkaline (99.8%) and acidic electrolytes (99.9%).