Mixed oxide-modified CaO catalysts from waste eggshells for efficient, reusable biodiesel production.

The oxygen reduction reaction (ORR) is a key process in energy conversion technologies, such as proton‐exchange membrane fuel cells, where catalyst efficiency directly impacts performance. Platinum (Pt)‐based alloy catalysts have emerged as a promising solution to improve ORR activity while reducing costs. Alloys, such as Pt–Ni, Pt–Co, Pt–Fe, and high‐entropy alloys (HEAs), offer enhanced catalytic performance due to synergistic interactions between Pt and the alloying element(s). These alloys can be tailored into distinct structural geometries, including core–shell structures, to optimize their electronic and structural properties for the ORR through various synthetic methods. Recent advancements have focused on fine‐tuning alloy compositions, doping, and morphologies to further improve stability and efficiency. In this perspective, the convergence of core–shell design and multimetallic alloying strategies is highlighted in addition to emphasizing their synergistic potential and addressing the practical hurdles associated with commercial applications. It highlights emerging trends in catalyst design, including the incorporation of non‐Pt metals and HEAs, and discusses strategies for enhancing the economic viability of Pt‐based catalysts in sustainable energy systems.