Durability is one of the most important characteristics of electrocatalysts used in low-temperature fuel cells with a proton exchange membrane. The degradation degree of deposited electrocatalysts containing platinum and platinum-copper nanoparticles with Pt-loading of about 20% by weight was assessed by voltammetric stress-testing, which corresponded to different mechanisms of degradation. The differences in the Pt-Cu nanoparticles architecture, caused by the peculiarities in their synthesis, affect the catalysts stability and their composition change due to the stress tests. It has been shown that at the close values of Pt-loading and electrochemically active surface area (ESA), the bimetallic catalysts on the Vulcan XC72 carbon carrier demonstrate significantly higher stability compared to commercial Pt/C catalysts. In this case, the "gradient" catalyst obtained by successive multi-stage copper and platinum deposition showed the highest residual activity in ORR, as well as resistance to stress testing and to the copper selective dissolution. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.