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Behavior of Pt/C catalysts obtained by the platinum deposition on standard and nitrogen-doped carbon supports with different microstructure has been studied in the oxygen electroreduction reaction in an acidic electrolyte. The catalysts based on the modified supports are characterized by a uniform spatial distribution of small-sized (1.5–2 nm) Pt nanoparticles over the surface of the supports, which results in high values of the electrochemically active surface area (110–130 m2 g− 1 (Pt)). The use of various stress testing protocols has shown that the Pt/C material based on the N-doped KetjenBlack EC DJ-600 possesses the highest mass activity and durability, which noticeably exceed the corresponding characteristics of the commercial HiSPEC3000 catalyst.

The electrodeposition of tin and tin-nickel on a highly dispersed carbon material is used to obtain composite supports. These composite supports were used in the Pt(0) nanoparticles deposition from Pt(IV) solution by chemical reduction. The composition, structure, and activity of the obtained Pt(SnO2/C) and PtSnNi/C catalysts in the oxygen reduction and alcohol electrooxidation reactions were studied. The composite-support-based platinum catalysts exhibit higher activity in the reactions of alcohols electrooxidation in comparison with the commercial Pt/C analogue. Trimetallic PtSnNi/C catalysts are the most promising materials for the electrooxidation of alcohols.

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.

The effect of the SnO2 nanoparticles content on the structure and electrochemical behavior of Pt/(SnO2/C) catalysts containing about 20 wt% Pt was studied. In this case, SnO2/C nanostructured materials were obtained by tin electrodeposition on the carbon particles in suspension. It was found that the optimal combination of stability and activity in the oxygen electroreduction reaction is demonstrated by materials containing 25–30% wt. SnO2. A comparative assessment of the durability and activity of Pt/(SnO2/C) catalysts and a commercial Pt/C catalyst with 20% Pt-loading has been carried out.

Electrocatalysts based on Pt-M bimetallic nanoparticles deposited on carbon supports have already been used in commercially available Proton Exchanged Membrane Fuel Cells (PEM FC). Nevertheless, production and practical use of such materials faces with the problems caused by the need to combine high specific activity in current-forming reactions and their durability, with the stability of the element's composition during the operation of PEM FC. The suggested stepwise approach to the PtCu/C materials synthesis in the liquid phase is based on the initial deposition of platinum nuclei and their subsequent growth due to the joint or sequential deposition of copper and platinum from the solutions of their precursors. The PtCu/C catalysts, obtained in this way, demonstrated not only higher activity in oxygen reduction reaction compared to the commercial Pt/C catalyst, but also a significantly higher corrosion-morphological stability.

Nitrogen-doped carbon materials were prepared by the pyrolysis of carbon black Vulcan XC-72 impregnated with nitrogen-containing Pd (II) and Ni (II) complexes. The composition of materials was studied at different stages of their synthesis. It is shown that nanoparticles of metals and/or their oxides are not the main electroactive component of materials in the oxygen electroreduction reaction (ORR). It is established that the palladium complex provides a much more efficient doping of carbon with nitrogen compared to the nickel complex of a similar composition. This results in the high ORR electrocatalytic activity of the catalyst obtained, palladium complex being used in an alkaline medium. This material is a promising one to be used as an electrocatalyst in fuel cells with an anion-conducting membrane.

The activity of PtCu/C catalysts in methanol electrooxidation is studied in HClO4 solution. The electrochemical behavior of catalysts is compared for samples in the “as obtained” state and after their pretreatment in nitric acid which decreases the copper content in their composition. It is found that the partial selective dissolution of the alloying component renders no negative effect on the behavior of bimetallic catalysts. The prepared materials exhibit the high tolerance toward intermediates of methanol oxidation and their specific activity exceeds by a factor of 5–7 the activity of the commercial Pt/C catalysts. The results of this study open up the possibility of using de-alloyed platinum-copper catalysts in alcohol fuel cells, because this considerably decreases the risk of contamination of the polymeric membrane.

The development of energy systems based on high specific power hydrogen–air fuel cells using domestic nanostructured materials and technologies is an urgent task. The technologies used for manufacturing proton-exchange membrane fuel cells (PEM FC) by the Russian company BMPower using Pt/C-electrocatalysts of the PM series produced by another Russian company, Prometheus R&D, are presented. It has been shown that, in terms of their functional characteristics, catalysts of the PM series are superior to imported analogues. The use of the PM40 catalyst, as well as other innovative solutions in the field of nanotechnology (nanostructured coatings of bipolar plates, formation of an ionomer on the catalytic layer) makes it possible to achieve a specific power of more than 1 kW/kg in the PEM FC power module with air cooling.

Platinum-containing bimetallic nanoparticles manifest high functional characteristics as electrocatalysts. To use PtCu/C catalysts in low-temperature fuel cells, it is necessary to minimize selective copper dissolution, as copper cations can pollute the polymer membrane and decrease its proton conductivity. The work determines the composition, measures the electrochemically active surface area, and studies the electrochemical behavior of PtCu/C catalysts containing nanoparticles with a “core–shell” structure in the initial state (as-prepared) and after pretreatment in solutions of different acids. The comparative determination of catalyst activity in an electrochemical cell and their testing in a membrane-electrode assembly of fuel cells showed that pretreated PtCu/C materials with a much better stability as compared to Pt/C were also noninferior to the latter as regards their activity in the oxygen electroreduction reaction.

One of important problems associated with the use of Pt/C electrocatalysts in low-temperature fuel cells is their degradation due to oxidation of the carbon support. The use of noncarbon supports resistant to oxidation, for example, oxides of certain metals in the highest degree of oxidation is a promising direction. TiO2 with the high specific surface area (104 m2/g) is synthesized and used in fabrication of supported platinum catalysts. For Pt/TiO2 and carbon-containing composite Pt/TiO2+C, the electrochemically active surface area of platinum and the their activity in oxygen electroreduction reaction are estimated. The assessed stability of synthesized materials far exceeds the stability of commercial Pt/C catalysts.

New nanostructured Pt/(SnO2/C)-electrocatalyst (20 wt % Pt) is synthesized via platinum chemical deposited onto composite SnO2/C-support microparticles (4 wt % Sn). The composite support was prepared beforehand using unique method of the tin electrochemical deposition onto disperse carbon black particles. It was shown by X-ray diffraction and transmission electron microscopy that the platinum and tin oxide nanoparticles distributed over the carbon surface are sized 2.4 and 2.9 nm, respectively. Electrochemical measurements showed the obtained catalyst to approach the commercial Pt/C HiSPEC 3000 catalyst (20 wt % Pt) with respect to its mass-activity in the oxygen electroreduction reaction and to be superior thereto as for the electrochemically active surface area, stability in stress test, and activity in methanol electrooxidation reaction. The peculiarities in electrochemical behavior of the synthesized Pt/(SnO2/C)-electrocatalyst can be explained by the SnO2 nanoparticle effect on the platinum nanoparticle nucleation/growth, as well as presence of Pt–SnO2–C triple junction nanostructure at the surface. The Pt/SnO2 contact provides stable platinum-to-support adhesion and asserts bifunctional catalysis mechanism of the methanol electrooxidation. And the Pt/C junctions provide for electron supplying/retraction to or from the platinum nanoparticles.

Materials containing from 3.1 to 7.7 wt % of cobalt were obtained by electrodeposition of cobalt on Vulcan XC72 carbon powder in suspension. The composition and average diameter of CoO crystallites formed as result of cobalt oxidation in the process of filtering and drying materials, depending on the electrolysis conditions and electrolyte composition, were studied using thermogravimetry and XRD. It is shown that the maximum amount of cobalt can be deposited from electrolytes containing, along with cobalt sulfate, additives of copper and nickel sulfates. Calculations by the Scherrer equation showed that an increase in the CoO content leads to a decrease in the diameter of crystallites, the size of which is in the nano-range. The analysis of X-ray and electrochemical studies indicates the formation, in the course of the borohydride’s synthesis, of combined catalysts containing nanoparticles of the Pt3Co solid solution. The best PtCo/C material demonstrated significant improvement in ORR activity and superior stability compared to commercial Pt/C catalyst of the same platinum loading.

Platinum-carbon catalysts are widely used in manufacturing proton-exchange membrane fuel cells. Increasing Pt/C activity and stability is an urgent task, optimization of their structure seems to be one of the possible solutions. In the present paper, Pt/C electrocatalysts which contained small (2 - 2.6 nm) nanoparticles of a similar size, uniformly distributed over the surface of a carbon support, were obtained by the original method of liquid-phase synthesis. A comparative study of the structural characteristics, catalytic activity in the oxygen electroreduction reaction and durability of the synthesized catalysts, as well as their commercial analogs has been carried out. It was shown that the ordering of the structural and morphological characteristics of Pt/C catalysts makes it possible to reduce the negative effect of NPs small size on their stability. As a result, the obtained catalysts are significantly superior to their commercial analogs in ORR activity, but not inferior to them in terms of stability.

An original method for the preparation of Pt/C materials dispersed by means of platinum electrodeposition on the carbon particles which are in the form of suspension has been proposed. The materials were studied by XRD, cyclic voltammetry, SEM and TEM electron microscopy. The obtained Pt/C materials contain from 9 to 14 wt% Pt. The average size of platinum particles is from 7 to 15 nm; electrochemically active surface area of Pt/C is from 15 to 29 m2 g−1 (Pt). The resulting materials exhibit catalytic activity in the oxygen electroreduction reaction which predominantly flows through the 4-electron mechanism.

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.

PtCu/C electrocatalysts with similar compositions but different distributions of components in bimetallic nanoparticles were obtained by simultaneous and sequential reduction of copper(II) and platinum( IV) in a carbon suspension. The catalyst obtained by multistage synthesis while sequentially increasing the Pt(IV) concentration in the precursor solution added at each stage showed the highest stability and activity in oxygen electroreduction in acidic media. This catalyst was least liable to selective dissolution of copper during its operation. The influence of the architecture of bimetallic PtCu nanoparticles on the electrochemical behavior of the catalysts is due to the peculiarities of the structure rearrangement of nanoparticles during the enrichment of the protective surface layer with platinum.

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 electrocatalysts containing platinum and platinum-copper nanoparticles with ~20 wt % Pt was evaluated under the conditions of voltammetry stress testing corresponding to different degradation mechanisms. The effect of the difference in the architecture of Pt–Cu nanoparticles on the stability of catalysts and changes in their composition as a result of stress tests were studied. At close values of the electrochemically active surface area (ECAS), the carbon-supported bimetallic catalysts demonstrated significantly higher stability compared to the commercial Pt/C catalysts. The Pt(Cu)/C catalyst obtained by sequential deposition of copper and platinum showed the highest resistance to the degradation and selective dissolution of copper during the testing.

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 electrooxidation reaction of methanol. For bimetallic catalysts, the effect of heat treatment on their structural and functional characteristics is also studied. Among bimetallic catalysts in the as-obtained state, the Pt@Ni/C catalyst prepared by the subsequent reduction of nickel and platinum from solutions of their compounds exhibited the highest activity in the methanol electrooxidation, significantly exceeding that for the commercial Pt/C product. Heat treatment at 350°C increased the activity of the PtCo/C catalyst containing nanoparticles of a solid solution but adversely affected the tolerance of all the studied bimetallic catalysts to the intermediate products of methanol oxidation. All the studied Pt/(SnO2/C) materials demonstrated a higher mass activity in the electrooxidation reaction of methanol compared to commercial Pt/C and bimetallic systems, while the catalyst with a weight fraction of platinum of 12% and a molar ratio of Pt: SnO2 of 1: 1.1 showed the highest mass activity.

Supported PtCu/C electrocatalysts containing core–shell bimetallic PtCu nanoparticles were synthesized by sequential chemical reduction of Cu2+ and Pt(IV) in a carbon suspension, prepared on the basis of ethylene glycol–water solvent, and then treated at different temperatures in the range from 250 to 350 °C. The structural characterization of “as-prepared” PtCu nanoparticles and of those obtained after the thermal treatments was performed by transmission electron microscopy, X-ray diffraction, and Pt L3- and Cu K-edge extended X-ray absorption fine structure spectroscopy. The atomic cluster models of PtCu nanoparticles before and after the thermal treatment, reflecting the character of the components’ distribution, were generated. The electrochemical performance of the obtained PtCu/C electrocatalysts in oxygen reduction reaction was studied by cycling and linear voltammetry.

A number of new platinum-based catalysts with Pt loading from 15.2% to 17.3% was obtained by wet chemical synthesis. Ethylene glycol, formaldehyde, and formic acid were used as reducing agents. The synthesis was performed both at ambient conditions and when the solution was saturated with carbon monoxide. It was shown that the catalysts obtained in the CO environment possess a larger electrochemical active surface area (EСSA), 140–146 m2 g−1 (Pt), compared to the analogues that have been made at ambient conditions, 72–120 m2 g−1(Pt). This could be explained by a smaller platinum NPs average size as well as a very narrow distribution of their size. In contrast to the materials synthesized at ambient conditions, the ECSA values of the catalysts, obtained in the CO-saturated media, in fact, do not depend on the type of reducing agent and the synthesis conditions. Such catalysts demonstrate the best mass-activity in ORR, which is higher than that of the commercial Pt/C catalyst HiSPEC 3000 (20% of Pt loading) and the analogues obtained at ambient conditions. Distinctive features of the nanoparticles nucleation/growth and their structure were determined and studied when formic acid was applied as a reducing agent. Absorption processes of the CO molecules on the surface of platinum nuclei are a plausible explanation for the CO influence on nucleation/growth and, therefore, on the microstructure and EСSA, as well as other functional characteristics of Pt/C-catalysts.

The structure characteristics and the electrochemical behavior of Pt(Cu)/C electrocatalysts synthesized by consecutive deposition of copper and platinum on carbon-support microparticles is studied. The stability and catalytic activity of Pt(Cu)/C materials in reactions of oxygen electroreduction and methanol electrooxidation are assessed and compared with analogous characteristics of a commercial Pt/C material. It is shown that combining the method of galvanic displacement of Cu by Pt with the additional chemical deposition of Pt favors optimization of the structure and functional characteristics of Pt(Cu)/C electrocatalysts. The effect of thermal treatment on the characteristics and properties of electrocatalysts is studied and the optimal conditions of such pretreatment are revealed.

The architecture of bimetallic nanoparticles has strong influence on durability and activity of PtM/C electrocatalysts in the oxygen electroreduction (ORR) and the methanol electrooxidation reactions (MOR). In the present study the Pt0.8(Cu)/C electrocatalyst was obtained by the methods of successive multistage reduction of platinum and copper from the solutions of their precursors while platinum concentration in the matrix solution was increasing step by step. The composition, structural characteristics and electrochemical behavior of this material were compared with the Pt1.0Cu/C catalyst based on the nanoparticles of a solid solution, which was obtained by the combined single-step chemical reduction of precursors, as well as with a commercial Pt/C sample with the same Pt-loading (20% by weight). The catalyst based on the Pt–Cu gradient nanoparticles demonstrated the highest corrosion-morphological stability in the stress-test, as well as the highest activity in ORR and MOR in the HClO4 solutions. Both of the studied bimetallic catalysts lose a significant amount of copper during the standardizing cycling and the stress-test. In the stabilized composition of the “gradient catalyst” the residual copper content, however, is considerably higher than that of the catalyst with the solid solution nanoparticles. The positive features of the electrochemical behavior of Pt0.8(Cu)/C catalyst arise apparently due to the faster formation of a durable protective layer of platinum on the surface of nanoparticles in the process of functioning, compared to the analogue based on the nanoparticles of the solid solution. High stability and activity of Pt0.8(Cu)/C compared to the Pt/C analogue are associated with the larger size of the nanoparticles and the promoting influence of residual copper on the catalytical activity of platinum.

The need to reduce platinum content in PEMFC catalyst layers has sparked a new wave of interest in ways to control the microstructure of Pt/C catalysts, which must combine high platinum surface area and activity. A comparative study of platinum nanoparticle nucleation/growth under a liquid-phase synthesis of Pt/C materials, with formaldehyde and formic acid being used as reducing agents, has been carried out. Analysis of the color change in the reaction medium and the in situ spectral-kinetic studies performed with absorption spectroscopy, were used as methods to study the reactions kinetics. The effect of the synthesis temperature on the features of the Pt(IV) reduction stages, nucleation/growth of Pt(0) nanoparticles, as well as on the size of the resulting Pt nanoparticles were studied. The role of the ethylene glycol and its derivatives, formed in the reaction medium at high pH, in the processes of Pt(IV) reduction and in the Pt(0) nanoparticles formation, is shown. The positive effect of the dispersed carbon support on the morphological characteristics of the resulting Pt/C catalysts is demonstrated, with carbon being introduced into the reaction medium in the initial stage of the synthesis. The roles of homogeneous and heterogeneous phase formation in the synthesis of Pt nanoparticles and Pt/C materials in the liquid phase are estimated.

A comparative study of the nucleation/growth processes of the platinum nanoparticles has been carried out with and without ultraviolet (UV) radiation. Platinum‑carbon catalysts containing 20%wt Pt with the average crystallite size ranges from 1.3 to 3.6 nm obtained by the liquid phase synthesis, using various reducing agents. It is shown, that for materials obtained under UV irradiation action the electrochemically active surface area increases up to 80% in comparison with the analogs. Improvement in the functional characteristics of the catalysts is due to narrowing in the size distribution of Pt nanoparticles and an increase in the uniformity of their spatial distribution. The synthesized catalysts demonstrated mass activity in ORR, which significantly exceeded the commercial analog activity. The approaches to the production of nanomaterials shown in the article are of great applied importance, since they can be used for gram-level syntheses.

PtCu/C electrocatalysts with bimetallic PtCu nanoparticles were synthesized by successive chemical reduction of Cu2+ and Pt(IV) in a carbon suspension prepared based on an aqueous ethylene glycol solution. The atomic structure of as-prepared PtCu nanoparticles and nanoparticles subjected to thermal treatment at 350°C was examined using PtL 3 and CuK EXAFS spectra, transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). The results of joint analysis of TEM microphotographs, XRD profiles, and EXAFS spectra suggest that the synthesized electrocatalysts contain PtCu nanoparticles with a Cu core–Pt shell structure and copper oxides Cu2O and CuO. Thermal treatment of electrocatalysts at 350°C results in partial reduction of copper oxides and fusion of bimetallic nanoparticles with the formation of both homogeneous and ordered PtCu solid solutions.

The influence of the atmosphere composition (CO, Ar, air), in which wet synthesis of Pt/C electrocatalyst was carried out, on the structural and morphological characteristics, and electrochemical behavior of electrocatalysts have been studied. For comparison, commercial Pt/C electrocatalysts with the same platinum loading were also studied. It has been shown that the adsorption of CO molecules on the surface of the growing platinum nuclei leads to the decrease in the average size of the nanoparticles and the narrowing of the size distribution in the Pt/C. Homemade electrocatalysts, with the values of electrochemically active surface area being from 94 to 139 m2 g−1 (Pt), prove to be in no way inferior to their commercial counterparts in oxygen reduction reaction mass activity. Durability of the homemade Pt/C samples in accelerated stress tests exceeds durability of the commercial ones.

The operation-mode stability and the catalytic activity in electrode reactions are the most important properties of electrocatalysts that determine the possibility of using them in fuel cells. The negative linear correlations between stability and catalytic activity of a series of Pt/C and Pt–Cu/C materials in the oxygen electroreduction reaction are revealed and studied. A method of selecting electrocatalysts with the optimal combination of activity and stability is proposed. The Cu@Pt/C catalysts containing bimetallic nanoparticles with the core–shell architecture which demonstrate the anomalously high combination of activity and stability are synthesized.

Composite metal-carbon electrocatalysts PtCu/C containing core-shell bimetallic PtCu nanoparticles were synthesized by sequential chemical reduction of Cu (II) and Pt (IV) in carbon suspension, prepared on the basis of ethylene glycol–water solvent. The characterization of “as prepared” and obtained after the acid treatment PtCu nanoparticles was performed by TEM, XRD, Pt L 3 - and Cu K -edge extended X-ray absorption fine structures (EXAFS). The technique and computational code were proposed for visualization of components distribution over the volume of cluster, which represents the mean bimetallic nanoparticle, according to the values of structural parameters derived from EXAFS. By this technique, the cluster models of PtCu nanoparticles before and after acid treatment, reflecting the character of components’ distribution, were generated. The study of electrochemical performances of the obtained PtCu/C electrocatalyst revealed the similar oxygen reduction reaction (ORR) activity and increased durability compared to commercial Pt/C electrocatalyst E-TEK 20.