Screening Ternary Pt-Based Electrocatalysts for Oxygen Reduction Reaction By Scanning Electrochemical Microscopy

Abstract

Developing efficient electrocatalysts for oxygen reduction is effective to reduce the overpotentials in cathode for PEMFC and metal-oxygen battery. A high-throughput approach for developing materials is revolutionizing the current trial-and-error mode with great potential for accelerating the process. The aim of the study is screening ternary Pt-based electrocatalysts for oxygen reduction reaction (ORR) by scanning electrochemical microscopy (SECM) with tip generation-substrate collection (TG-SC) mode. Oxygen was generated at a tip and reduced at the electrocatalyst spots on substrate. Among several ternary Pt-based electrocatalyst arrays, Pt8Ni2Co0, Pt2Fe4Cu4, Pt6Mn2Mo2, Pt8Al2Tl0, Pt6V2Ga2 exhibit excellent electrocatalytic activity for ORR. The structure, morphology and oxidation state of these potential electrocatalysts are systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The tip/substrate voltammetry, approach curves and rotating disk electrode analysis are further used to examine the kinetics of the potential electrocatalysts toward oxygen reduction reaction.