# Pd/MnO2:Pd/C Electrocatalysts for Efficient Hydrogen and Oxygen Electrode Reactions in AEMFCs

## TL;DR

This study develops a hybrid electrocatalyst that improves the efficiency and durability of fuel cells using palladium and manganese oxide.

## Contribution

A novel hybrid electrocatalyst combining Pd/MnO2 and Pd/C is proposed for enhanced bifunctional performance in AEMFCs.

## Key findings

- The hybrid electrocatalyst achieved peak power densities of 128.0 mW cm−2 as a cathode and 221.7 mW cm−2 as an anode.
- The hybrid retained over 99% of its initial activity after 3000 cycles, demonstrating high durability.
- MnO2 enhances mass transport and stability while carbon ensures efficient electron transport.

## Abstract

Developing cost-effective and durable electrocatalysts is essential for advancing anion exchange membrane fuel cells (AEMFCs). This work evaluates Pd-based catalysts supported on β-MnO2, Vulcan carbon (C), and their physical blend (Pd/MnO2:Pd/C) as bifunctional electrodes for the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR). The catalysts were synthesized via chemical reduction and characterized by TGA, ICP-OES, TEM, BET, and XRD. Rotating disk electrode studies revealed that the hybrid exhibited superior activity and kinetics, with lower Tafel slopes and higher exchange current densities compared to the individual supports. In AEMFCs, the hybrid reached 128.0 mW cm−2 as a cathode and 221.7 mW cm−2 as an anode, outperforming individual components. This enhanced performance arises from the synergistic interaction between Pd nanoparticles and MnO2, where MnO2 modulates the catalyst’s microstructure and local reaction environment while the carbon phase ensures efficient electron transport. MnO2, although inactive for the HOR alone, acted as a structural spacer, enhancing mass transport and stability. Durability tests confirmed that the hybrid electrocatalyst retained over 99% of its initial activity after 3000 cycles. These results highlight the hybrid Pd/MnO2:Pd/C as a promising, bifunctional, and durable electrocatalyst for AEMFC applications.