Sergey V. Belenov

This work presents a promising method for synthesizing high-performance PtCo/C–N catalysts based on Pt/C material on an N-doped carbon carrier. The effect of treatment temperature of Pt/C–N materials with deposited cobalt precursors on the structure and catalytic activity of PtCo/C–N catalysts has been studied. It was found that an increase in the treatment temperature from 600 to 800 °C leads to a slight growth in nanoparticle size from 2.2 to 2.6 nm (according to XRD) and a decrease in the electrochemical surface area from 90 to 69 m2/g(Pt). After high-temperature synthesis, the activity of the resulting bimetallic PtCo/C–N catalysts is 3–4 times higher than that of the initial Pt/C–N material or the commercial Pt/C benchmark in the potential range of 0.95–0.87 V. The PtCo/C–N material after treatment at 600 °C demonstrated the highest oxygen reduction reaction activity after accelerated stress testing. The obtained PtCo/C–N catalysts are promising materials for the further optimization of the membrane electrode assembly (MEA) catalyst layer and for investigating their long-term stability in MEAs to assess their potential for use in commercial proton-exchange membrane fuel cells (PEMFCs).

The aim of this work was high-temperature synthesis of PtPdCoNiCu/C nanoparticles with high-entropy alloy (HEA) structure as catalysts for oxygen reduction reaction. The materials were synthesized using a highly dispersed PtPd/C support, which was impregnated with Cu, Ni, and Co precursors followed by their precipitation with an alkali. Subsequently, the material was subjected to thermal treatment in a tube furnace at 600 °C for 1 h in a stream of argon containing 5% hydrogen. In combination with HRTEM, element mapping and line scan, XRD, and XPS data, these results confirm the successful synthesis of five-component PtPdCoNiCu high-entropy alloy nanoparticles on the surface of the carbon support. The obtained materials are characterized by a high electrochemical surface area of up to 63 m²/g(PGM), as determined by hydrogen adsorption/desorption and CO-stripping, and a high specific oxygen reduction reaction (ORR) activity of approximately 269 A/g(PGM) at 0.9 V vs. RHE. The synthesized material demonstrated outstanding stability, as confirmed by an accelerated stress test of 10,000 cycles. After the test, the electrochemical surface area decreased by only 12%, while the catalytic activity for ORR even increased. The proposed synthetic strategy opens a new pathway for obtaining promising highly stable five-component HEA nanoparticles of various compositions for application in catalysts.

This report introduces a high-performance bimetallic electrocatalyst for the oxygen reduction reaction (ORR) featuring a 20 wt.% platinum content. The PtCu-based catalyst combines de-alloyed nanoparticles (NPs) supported on nitrogen-doped carbon. Enhanced uniformity in NP distribution significantly boosts the catalyst performance. Nitrogen-doped carbon provides active centers for NP deposition, which is confirmed by HAADF-STEM and EDX. The PtCu/CN catalyst achieves over 5.6 times the ORR mass activity and two times the stability under pulse cycling compared to commercial Pt/C. Uniquely, the study examines bimetallic NPs and local nano-sites before and after stress testing using IL-TEM. In situ analysis of PtCu/CN microstructure revealed two primary degradation mechanisms, (i) partial dissolution of NPs and (ii) NP agglomeration, with the C–N support significantly mitigating these effects through strong NP–support interactions. The findings underscore the prospects of bimetallic PtCu catalysts with nitrogen-doped support by showcasing exceptional ORR activity and durability.

Bimetallic platinum-containing catalysts are deemed promising for electrolyzers and proton-exchange membrane fuel cells (PEMFCs). A significant number of laboratory studies and commercial offers are related to PtNi/C and PtCo/C electrocatalysts. The behavior of PtPd/C catalysts has been studied much less, although palladium itself is the metal closest to platinum in its properties. Using a series of characterization methods, this paper presents a comparative study of structural characteristics of the commercial PtPd/C catalysts containing 38% wt. of precious metals and the well-known HiSpec4000 Pt/C catalyst. The electrochemical behavior of the catalysts was studied both in a three-electrode electrochemical cell and in the membrane electrode assemblies (MEAs) of hydrogen–air PEMFCs. Both PtPd/C samples demonstrated higher values of the electrochemically active surface area, as well as greater specific and mass activity in the oxygen reduction reaction in comparison with conventional Pt/C, while not being inferior to the latter in durability. The MEA based on the best of the PtPd/C catalysts also exhibited higher performance in single tests and long-term durability testing. The results of this study conducted indicate the prospects of using bimetallic PtPd/C materials for cathode catalysts in PEMFCs.

The presented study is concerned with a new multi-step method to synthesize PtCo/C materials based on composite Co_xO_y/C that combines the advantages of different liquid-phase synthesis methods. Based on the results of studying the materials at each stage of synthesis with the TG, XRD, TEM, SEI, TXRF, CV and LSV methods, a detailed overview of the sequential changes in catalyst composition and structure at each stage of the synthesis is presented. The PtCo/C catalyst synthesized with the multi-step method is characterized by a uniform distribution of bimetallic nanoparticles of about 3 nm in size over the surface of the support, which result in its high ESA and ORR activity. The activity study for the synthesized PtCo/C catalyst in an MEA showed better current–voltage characteristics and a higher maximum specific power compared with an MEA based on a commercial Pt/C catalyst. Therefore, the results of the presented study demonstrate high prospects for the developed approach to the multi-step synthesis of PtM/C catalysts, which may enhance the characteristics of proton-exchange membrane fuel cells (PEMFCs).