To obtain the PtRu/C electrocatalysts, the surfactant-free (wet) synthesis methods have been used. The structural-morphological characteristics and electrochemical behavior of the catalysts have been studied. The possibility of ranging the crystallite size from 1.2 to 4.5 nm using different reducing agents (ethylene glycol, ethanol, and isopropanol) has been shown. The effect of both the particles’ size and the mass fraction of the metal component on the electrochemical surface area (ESA), activity in the methanol electrooxidation reaction (MOR), and tolerance to its intermediate products has been studied. The simple and scalable surfactant-free synthesis method of the highly active PtRu/C electrocatalysts with a different mass fraction of metals, with their tolerance to intermediate products of the oxidation being 2.3 times higher than the commercial analogue, has been first proposed. The authors have succeeded in obtaining the PtRu/C catalysts with the nanoparticles’ size of less than 2 nm, characterized by the ultranarrow size and uniform spatial distributions over the support surface, thus having the ESA of more than 90 m2gPtRu−1.