The composites of transition metal-doped titania and carbon have emerged as promising supports for Pt electrocatalysts in PEM fuel cells. In these multifunctional supports, the oxide component stabilizes the Pt particles, while the dopant provides a co-catalytic function. Among other elements, Sn is a valuable additive. Stong metal-support interaction (SMSI), i.e., the migration of a partially reduced oxide species from the support to the surface of Pt during reductive treatment is a general feature of TiO₂-supported Pt catalysts. In order to explore the influence of SMSI on the stability and performance of Pt/Ti_0.8Sn_0.2O₂-C catalysts, the structural and catalytic properties of the as prepared samples measured using XRD, TEM, XPS and electrochemical investigations were compared to those obtained from catalysts reduced in hydrogen at elevated temperatures. According to the observations, the uniform oxide coverage of the carbon backbone facilitated the formation of Pt–oxide–C triple junctions at a high density. The electrocatalytic behavior of the as prepared catalysts was determined by the atomic closeness of Sn to Pt, while even a low temperature reductive treatment resulted in Sn–Pt alloying. The segregation of tin oxide on the surface of the alloy particles, a characteristic material transport process in Sn–Pt alloys after oxygen exposure, contributed to a better stability of the reduced catalysts.

TiO₂-based mixed oxide–carbon composite support for Pt electrocatalysts provides higher stability and CO tolerance under the working conditions of polymer electrolyte membrane fuel cells compared to traditional carbon supports. Non-traditional carbon materials like graphene nanoplatelets and graphite oxide used as the carbonaceous component of the composite can contribute to its affordability and/or functionality. Ti_(1−x)Mo_xO₂-C composites involving these carbon materials were prepared through a sol–gel route; the effect of the extension of the procedure through a solvothermal treatment step was assessed. Both supports and supported Pt catalysts were characterized by physicochemical methods. Electrochemical behavior of the catalysts in terms of stability, activity, and CO tolerance was studied. Solvothermal treatment decreased the fracture of graphite oxide plates and enhanced the formation of a reduced graphene oxide-like structure, resulting in an electrically more conductive and more stable catalyst. In parallel, solvothermal treatment enhanced the growth of mixed oxide crystallites, decreasing the chance of formation of Pt–oxide–carbon triple junctions, resulting in somewhat less CO tolerance. The electrocatalyst containing graphene nanoplatelets, along with good stability, has the highest activity in oxygen reduction reaction compared to the other composite-supported catalysts.

Sn-doped TiO₂–carbon composites were identified as promising multifunctional supports for Pt electrocatalysts, in which the oxide component enhances resistance against corrosion and strong metal–support interactions at the Pt-oxide boundary ensure high stability for the Pt nanoparticles. This work is devoted to the study of the influence of preliminary functionalization of the carbon on the properties of Pt/Ti_0.9Sn_0.1O₂–C catalysts. The structural, compositional and morphological differences between the samples prepared using functionalized or unmodified carbon, as well as the effect of carbon pre-modification on the electrocatalytic behavior of the synthesized Pt catalysts, were investigated using TEM, XRD, XPS, nitrogen adsorption and electrochemical measurements. The presence of oxygen-containing functional groups on carbon treated with HNO₃ and glucose leads to the formation of a homogeneous coating of the carbon with dispersed crystallites of mixed oxide. Elemental mapping revealed the proximity of Sn species with highly dispersed (2–3 nm) Pt particles. Notably, the electrochemical results indicated enhanced activity in CO electrooxidation for both functionalized and unmodified carbon-containing catalysts. An improvement in the 10,000-cycle long-term stability of the catalyst prepared using functionalized carbon was evident compared to the catalyst with untreated carbon or reference Pt/C.