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 PtCux/C catalysts were prepared by a multistage sequential deposition of copper and platinum onto a Vulcan XC72 dispersed carbon support. De-alloyed PtCux−y/C catalysts were prepared by PtCux/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.
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 PtCux/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 PtCux/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 PtCux-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.
1 November 2018 in Russian Journal of Electrochemistry
We investigate the activity of bimetallic PtM/C (M = Ni, Co) catalysts with different microstructures and platinum catalysts supported on a nanostructured composite carrier (SnO2/C) in the...
1 November 2018 in Russian Journal of Electrochemistry
Stability is one of the most important characteristics of electrocatalysts used in low-temperature fuel cells with a proton exchange membrane. The corrosion-morphological stability of supported...
1 June 2021 in Russian Journal of Electrochemistry
Catalysts containing bimetallic PtCu-nanoparticles deposited onto carbonaceous and composite SnO2/C supports are prepared by liquid-phase borohydride synthesis. The composition and structure of the synthesized materials, their catalytic activity in the reactions of oxygen electroreduction and methanol electrooxidation, as well as corrosion and morphological stability are investigated. The platinum doping with copper atoms is found to increase the materials’ catalytic activity and stability in comparison with Pt/C, regardless of the type of support used. In addition, the multicomponent PtCu/(SnO2/C) catalyst exhibits the highest tolerance to intermediate products of methanol electrooxidation.