As the demand for sustainable energy solutions grows, developing efficient energy conversion and storage technologies, such as fuel cells and metal-air batteries, is vital. Oxygen Reduction Reaction (ORR) is a significant limitation in electrochemical systems due to its slower kinetics. Although Pt-based catalysts are commonly used to address this challenge, their high cost and suboptimal performance remain significant obstacles to further development. This review offers a comprehensive overview of advanced support materials aimed at improving the efficiency, durability, and cost-effectiveness of Pt-based catalysts. By examining a range of materials, including mesoporous carbon, graphene, carbon nanotubes, and metal oxides, the review clarifies the relationship between the structural properties of these supports and their influence on ORR performance. Additionally, it discusses the fundamental characteristics of these materials, their practical applications in fuel cells, and explores potential solutions and future directions for optimizing Pt-based catalysts to advance sustainable energy conversion technologies. Future research could focus on nano-engineering and composite material development to unlock the full potential of Pt-based catalysts, significantly enhancing their economic viability and performance in energy applications.

The chemical stability of anion polymer electrolyte membranes (AEMs) determines the durability of an AEM water electrolyzer (AEMWE). The alkaline stability of AEMs has been widely investigated in the literature. However, the degradation of AEM at neutral pH closer to the practical AEMWE operating condition is neglected, and the degradation mechanism remains unclear. This paper investigated the stability of quaternized poly(p-phenylene oxide) (QPPO)-based AEMs under different conditions, including Fenton solution, H₂O₂ solution and DI water. The pristine PPO and chloromethylated PPO (ClPPO) showed good chemical stability in the Fenton solution, and only limited weight loss was observed, 2.8% and 1.6%, respectively. QPPO suffered a high mass loss (29%). Besides, QPPO with higher IEC showed a higher mass loss. QPPO-1 (1.7 mmol g⁻¹) lost nearly twice as much mass as QPPO-2 (1.3 mmol g⁻¹). A strong correlation between the degradation rate of IEC and H₂O₂ concentration was obtained, which implied that the reaction order is above 1. A long-term oxidative stability test at pH neutral condition was also conducted by immersing the membrane in DI at 60 °C water for 10 months. The membrane breaks into pieces after the degradation test. The possible degradation mechanism is that oxygen or OH˙ radicals attack the methyl group on the rearranged ylide, forming aldehyde or carboxyl attached to the CH₂ group.