Fabrication and electrochemical investigations of nanostructured PtSn-NiTiO3 heterostructured electrocatalysts for direct methanol oxidation

The methanol oxidation reaction of a PtSn nanoparticle decorated NiTiO₃ nanostructured material system is reported in this paper. NiTiO₃ and PtSn nanoparticles were formed in rhombohedral and cubic phases, respectively. The crystallite size of the PtSn nanoparticles was calculated to be 2.8 nm from the XRD peak parameters and TEM studies. The surface plasmon resonance peak observed at 308 nm indicates the decoration of PtSn-NiTiO₃ nanostructures with Pt nanoparticles on the surface. The chemical oxidation states investigated by XPS showed a metallic state of Pt and Sn with a small amount of surface oxidization. From the electrochemical analysis, the Pt_0.5Sn_0.5-NiTiO₃ nanostructures showed superior electrocatalytic performance with higher electrochemical surface area (252 m²/g), high current density (196 mA/cm²), lower Tafel value (161.31 mV/dec) and small charge transfer resistance. This work demonstrated that the Pt_0.5Sn_0.5 −NiTiO₃ nanostructure would be a suitable electrocatalyst for oxidation for methanol in DMFC.