Positive Impact of Acid‐Heat Treatment on the Electrocatalytic Performance of Highly Active and Low Pt‐Based Nanostructured Alloy Catalysts for Oxygen Reduction Reactions to Electrochemical Energy Conversion Devices

Platinum‐based catalysts have been widely examined for energy conversion devices and other applications. However, a significant reduction in costs by reducing the amount of precious Pt in the catalyst without reducing its effectiveness is necessary for large‐scale commercialization. In this regard, low‐Pt alloyed with 3d transition‐metal (M = Co, Ni, Cr) catalysts supported by carbon have been synthesized. Here, an inexpensive, simple, and fast dry‐mixing method and an alloying process using a rapid quenching technique are used for the synthesis of PtM/C catalysts. After synthesis, an acid‐heat treatment is conducted to reconstruct the surface of nanoparticle (NP) catalysts. The result shows that acid‐heat treatment eliminates surface oxidation and reduces the size of NPs, resulting in increased active surface area and the number of Pt‐active sites. Acid‐heat treatment also modifies the composition ratio of NPs, leading to the uniform dispersion of Pt and M atoms in the alloy. Oxygen reduction reaction activity of PtM/C alloy catalysts after acid‐heat treatment has improved considerably, and this improvement depends on the unique structural features of Pt and M. Among the different catalysts, PtCo/C has the highest electrocatalytic activity because of the effective modification of electronic surface structure and the increased number of active sites. Oxygen reduction reaction activity of the easy synthesis of PtM/C catalysts has been increased after acid‐heat treatment, and among these catalysts, PtCo/C exhibits higher performance due to increased active reaction sites and modified electronic surface structure. This study represents not only the exploration of a rational conception of alloy nanoparticle systems but also highlights the control system of morphology, composition, and electronic structure.