The behavior of supported alloyed and de-alloyed platinum-copper catalysts, which contained 14–27% wt. of Pt, was studied in the reactions of methanol electrooxidation (MOR) and oxygen electroreduction (ORR) in 0.1 M HClO₄ solutions. Alloyed PtCu_x/C catalysts were prepared by a multistage sequential deposition of copper and platinum onto a Vulcan XC72 dispersed carbon support. De-alloyed PtCu_x−y/C catalysts were prepared by PtCu_x/C materials pretreatment in acid solutions. The effects of the catalysts initial composition and the acid treatment condition on their composition, structure, and catalytic activity in MOR and ORR were studied. Functional characteristics of platinum-copper catalysts were compared with those of commercial Pt/C catalysts when tested, both in an electrochemical cell and in H₂/Air membrane-electrode assembly (MEA). It was shown that the acid pretreatment of platinum-copper catalysts practically does not have negative effect on their catalytic activity, but it reduces the amount of copper passing into the solution during the subsequent electrochemical study. The activity of platinum-copper catalysts in the MOR and the current-voltage characteristics of the H₂/Air proton-exchange membrane fuel cell MEAs measured in the process of their life tests were much higher than those of the Pt/C catalysts.

Using the methods of powder X-ray diffraction, transmission electron microscopy, and EXAFS spectroscopy, the phase behavior of bimetallic Pt–Cu nanoparticles with different architecture that are deposited on a highly disperse carbon carrier has been investigated during their thermal treatment in inert atmosphere. It is established that Pt–Cu nanoparticles with a Cu-core–Pt-shell structure rearrange into nanoparticles with a Pt–Cu solid-solution structure in the temperature range from 280 to 300°C. This transformation is accompanied by a sharp change in the unit-cell parameter. Such a change in the crystal lattice parameter does not occur during the thermal treatment of material with similar composition containing Pt–Cu nanoparticles with a solid-solution structure. The results can be used in elucidating the structure of Pt–M/C materials with different nanoparticle architectures.

Electrooxidation of methanol, ethanol, and formic acid was studied on three platinum-containing electrocatalysts: PtCu/C, Pt/(SnO₂/C), and Pt/C, Pt content being about 20 wt%. In all reactions, the integral specific activity of the catalysts, estimated from the results of cyclic voltammetry, grows in the Pt/C < Pt/(SnO₂/C) < PtCu/C row. The influence of the reagent nature subjected to electrooxidation is manifested both in the difference of the absolute rate values of the corresponding reactions, decreasing in the order CH₃OH > HCOOH > C₂H₅OH, and in the different ratio of these rates on different catalysts and at different potentials. Pt/(SnO₂/C) catalyst containing SnO₂ nanoparticles is the most active among the studied catalysts in methanol and formic acid electrooxidation reactions under potentiostatic conditions at the E = 0.60 V. Moreover, in formic acid electrooxidation reaction it is significantly superior to even the PtRu/C commercial catalyst. The reasons for the positive influence of Cu atoms and SnO₂ nanoparticles on the catalytic activity of platinum are presumably associated with different effects: Interaction of the d-orbitals of copper and platinum atoms in bimetallic nanoparticles and implementation of the bifunctional catalysis mechanism on the adjacent platinum and tin dioxide nanoparticles.

PtM/C (M = Co, Ni, Cu, Ru) catalysts were prepared by wet-synthesis methods. The composition and structure of the synthesized materials were estimated by TXRF, XRD, TEM, HAADF-STEM, EDX, and TGA/DSC methods. According to the CV and LSV methods, the PtCu/C material is characterized by the highest activity in the ORR compared to the other materials studied. The PtRu/C catalysts also exhibit the highest activity in the MOR. Studying the durability of the obtained bimetallic catalysts using accelerated stress testing has allowed for the detection of the most promising materials, whose characteristics would be superior to those of the commercial Pt/C analog. This study has shown that wet-synthesis methods allow obtaining bimetallic catalysts characterized by higher activity and enhanced durability. This research also indicates that special attention should be given to the possibility of scaling these synthesis techniques, which makes the aforementioned catalysts promising for commercial applications.

A carbon supported PtCu_x/C catalyst, which demonstrates high activity in the oxygen electroreduction and methanol electrooxidation reactions in acidic media, has been obtained using a method of chemical reduction of Pt (IV) and Cu (2+) in the liquid phase. It has been found that the potential range of the preliminary voltammetric activation of the PtCu_x/C catalyst has a significant effect on the de-alloyed material activity in the oxygen electroreduction reaction (ORR). High-resolution transmission electron microscopy (HRTEM) demonstrates that there are differences in the structures of the as-prepared material and the materials activated in different potential ranges. In this case, there is practically no difference in the composition of the PtCu_x-y/C materials obtained after activation in different conditions. The main reason for the established effect, apparently, is the reorganized features of the bimetallic nanoparticles’ surface structure, which depend on the value of the limiting anodic potential in the activation process. The effect of the activation conditions on the catalyst’s activity in the methanol electrooxidation reaction is less pronounced.