A detailed study of the structure, morphology and electrochemical properties of Pt/C and Pt/x-SnO₂/C catalysts synthesized using a polyol method has been provided. A series of catalysts supported on the SnO₂-modified carbon was synthesized and studied by various methods including transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical methods, and fuel cell testing. The SnO₂ content varies from 5 to 40 wt %. The TEM images, XRD and XPS analysis suggested the Pt-SnO₂ hetero-clusters formation. The SnO₂ content of ca. 10% ensures an optimal catalytic layer structure and morphology providing uniform distribution of Pt-SnO₂ clusters over the carbon support surface. Pt/10wt %-SnO₂/C catalyst demonstrates increased activity and durability toward the oxygen reduction reaction (ORR) in course of accelerated stress testing due to the high stability of SnO₂ and its interaction with Pt. The polymer electrolyte membrane fuel cell current–voltage performance of the Pt/10wt %-SnO₂/C is comparable with those of Pt/C, however, higher durability is expected.

The global issue for proton exchange membrane fuel cell market development is a reduction in the device cost through an increase in efficiency of the oxygen reduction reaction occurring at the cathode and an extension of the service life of the electrochemical device. Losses in the fuel cell performance are due to various degradation mechanisms in the catalytic layers taking place under conditions of high electric potential, temperature, and humidity. This review is devoted to recent advances in the field of increasing the efficiency and durability of electrocatalysts and other electrode materials by introducing structured carbon components into their composition. The main synthesis methods, physicochemical and electrochemical properties of materials, and performance of devices on their basis are presented. The main correlations between the composition and properties of structured carbon electrode materials, which can provide successful solutions to the highlighted issues, are revealed.

In this study, we performed small-angle X-ray scattering (SAXS) to investigate the structure of Nafion^® membranes. The effect of freeze/thaw (F/T) cycles (from ambient temperature down to −40 °C) on the membrane nanostructure was considered for the first time. The SAXS measurements were taken for different samples: a commercial Nafion^® 212 membrane swollen in water and methanol solution, and a water-swollen silica-modified membrane. The membrane structure parameters were obtained from the measured SAXS profiles using a model-dependent approach. It is shown that the average radius of water channels (R_wc) decreases during F/T cycles due to changes in the membrane structure as a result of ice formation in the pore volume after freezing. The use of water-methanol solution (methanol content of 20 vol.%) for the membrane soaking prevents changes in the membrane structure during F/T cycles compared to the water-swollen membrane. Modification of the membrane surface with silica (SiO₂ content of 20 wt.%) led to a redistribution of water in the membrane volume and resulted in a decrease in R_wc. However, R_wc for the modified membrane did not decrease with the increasing number of F/T cycles due to the involvement of SiO₂ in the sorption of membrane water and, therefore, the prevention of ice formation.