# Maximal electrocatalytic activity of Sr-doped Nd1−xSrxMnO3 perovskite oxides (x = 0.1, 0.2, 0.3) towards ORR: for next-generation power systems

## TL;DR

This paper shows that Sr-doped Nd1−xSrxMnO3 perovskite oxides are highly effective electrocatalysts for oxygen reduction reactions, outperforming platinum-based catalysts in some aspects.

## Contribution

The study identifies NSM-0.7 as a superior electrocatalyst for ORR due to optimal Sr-doping at the perovskite's A-site.

## Key findings

- NSM-0.7 (Nd0.7Sr0.3MnO3) achieved an onset potential of 0.82 V vs. RHE and a half-wave potential of 0.58 V vs. RHE.
- NSM-0.7 exhibited a kinetic current density of 0.41 mA cm−2 and favored a 4e− pathway with minimal H2O2 formation.
- NSM-0.7 demonstrated superior stability compared to Pt/C catalysts in electrocatalytic applications.

## Abstract

By using the sol–gel method, a series of Nd1−xSrxMnO3 perovskite oxides (x = 0.1, 0.2, 0.3), designated as NSM-0.9, NSM-0.8, and NSM-0.7, were prepared and characterized using analytical techniques including XRD, FESEM, TEM, EDS, and XPS. Our investigation revealed that NSM-0.7 (Nd0.7Sr0.3MnO3) is the most effective electrocatalyst for the oxygen reduction reaction (ORR). Its superior electrocatalytic performance in a 0.1 M KOH solution, evaluated with RDE and RRDE techniques, was quantified by an onset potential (Eon) of 0.82 V vs. RHE, a half-wave potential (E1/2) of 0.58 V vs. RHE, a limiting current density (JL) of −5 mA cm−2, which is the same as the current density of Pt/C, and a kinetic current density (Jk) of 0.41 mA cm−2 at 1600 rpm. This material also favoured a highly efficient 4e− pathway with the formation of a minimal amount of H2O2. NSM-0.7's superior catalytic performance is attributed to optimal Sr-doping at the perovskite's A-site, a process that significantly enhances its Mn valence and oxygen adsorption capacity. Furthermore, chronoamperometry confirmed that NSM-0.7 exhibits superior stability compared to the benchmark Pt/C catalyst, demonstrating that strategic A-site doping is a promising approach for improving conventional perovskite oxides for electrocatalytic applications.

Nd1−xSrxMnO3 perovskite oxides (x = 0.1, 0.2, 0.3), designated as NSM-0.9, NSM-0.8, and NSM-0.7, were prepared by Sol–Gel method and their electrocatalytic properties towards ORR was evaluated.