Activity and stability of PtCo/C electrocatalysts for alcohol oxidation

This study considers the liquid-phase synthesis of PtCo/C catalysts based on CoOx/C composite carriers with different mass fractions of metals and Pt:Co ratios. The purpose of the article is to study the activity of PtCo/C electrocatalysts of various compositions in the oxidation reactions of methanol and ethanol and to compare their characteristics with their commercial PtRu/C and Pt/C analogues. PtCo/С catalysts were synthesised with Pt:Co ratios of 1:1 and 3:1. The specific active surface of the obtained PtCo/C materials was determined, their activity in the oxidation reactions of methanol and ethanol and their resistance to poisoning by intermediate products of alcohol oxidation were studied. The structural and electrochemical characteristics of the obtained PtCo/C catalysts were studied by X-ray diffraction, cyclic voltammetry, and chronoamperometry. It was found that PtCo/C materials with a mass fraction of platinum close to 20% are the most active and stable as compared to their commercial PtRu/C and Pt/C analogues. The presented results show that PtCo/C catalysts are a promising material for direct alcohol fuel cells

Influence of caprolactam on the tin electrodeposition on a dispersed carbon support and preparation of Pt/(SnO2/C) catalysts

Composite SnO2/C materials obtained by electrodeposition of tin on Vulcan XC72 particles were used to fabricate a platinum catalyst for the oxygen electroreduction reaction (ORR). Thermogravimetry and X-ray diffraction methods made it possible to determine the composition of materials and the size of platinum and tin oxide crystallites. The use of the SnO2/C composite obtained in the presence of e-caprolactam (CPL) as a support made it possible to increase the electrochemically active surface area (ESA) of platinum and the mass activity of the Pt/SnO2/C catalyst in ORR

Memory Effect: How the Initial Structure of Nanoparticles Affects the Performance of De-Alloyed PtCu Electrocatalysts?

An important feature of this research is the investigation of the de-alloyed catalysts based on the nanoparticles with a simple structure (alloy) and a complex structure (gradient). The resulting samples exhibit the 2–4 times higher mass activity in the ORR compared with the commercial Pt/C. The novelty of this study is due to the application of the express-electrochemical experiment to register the trend of changes in the ORR activity caused by rearranging the structure of bimetallic nanoparticles. The state-of-the-art protocol makes it possible to establish the dependence of properties of the de-alloyed catalysts on the nanoparticles’ structure obtained at the stage of the material’s synthesis. The study shows the possibility of determining the rate of the ongoing reorganization of bimetallic nanoparticles with different architectures. The PtCu/C electrocatalysts for proton-exchange membrane fuel cells presented in this work are commercially promising in terms of both the high functional characteristics and the production by facile one-pot methods

Memory Effect: How the Initial Structure of Nanoparticles Affects the Performance of De-Alloyed PtCu Electrocatalysts?

An important feature of this research is the investigation of the de-alloyed catalysts based on the nanoparticles with a simple structure (alloy) and a complex structure (gradient). The resulting samples exhibit the 2–4 times higher mass activity in the ORR compared with the commercial Pt/C. The novelty of this study is due to the application of the express-electrochemical experiment to register the trend of changes in the ORR activity caused by rearranging the structure of bimetallic nanoparticles. The state-of-the-art protocol makes it possible to establish the dependence of properties of the de-alloyed catalysts on the nanoparticles’ structure obtained at the stage of the material’s synthesis. The study shows the possibility of determining the rate of the ongoing reorganization of bimetallic nanoparticles with different architectures. The PtCu/C electrocatalysts for proton-exchange membrane fuel cells presented in this work are commercially promising in terms of both the high functional characteristics and the production by facile one-pot methods

Reasons for the Differences in the Kinetics of Thermal Oxidation of the Support in Pt/C Electrocatalysts

High-temperature oxidation processes of carbon microparticles Vulcan XC72 coated with platinum nanoparticles (Pt/C) were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The presence of different specific temperature ranges in the oxidation of carbon support was shown to be due to both the peculiarities of granulometric composition of carbon black microparticles, different size, and uneven spatial distribution of platinum nanoparticles in the pores and on the surface of the carbon support. The correlation between the length of a section in the thermograms and the fraction of carbon microparticles poorly coated with platinum can be used to analyze the uniformity of Pt nanoparticle spatial distribution in the metal–carbon catalysts and therefore to select electrocatalysts with optimal microstructure. This analysis is expected to be effectively utilized in order to assess the uniformity of platinum distribution on carbon microparticles and also to provide additional information about granulometric composition of carbon supports