Hexagonal nanorods of tungsten trioxide: Synthesis, structure, electrochemical properties and activity as supporting material in electrocatalysis

• Published in: Applied surface science 2011-07, Vol.257 (19), p.8223-8229
• Main Authors: Salmaoui, Samiha, Sediri, Faouzi, Gharbi, Néji, Perruchot, Christian, Aeiyach, Salah, Rutkowska, Iwona A., Kulesza, Pawel J., Jouini, Mohamed
• Format: Article
• Language: English
• Subjects: Anodizing; Channels; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Ethyl alcohol; Exact sciences and technology; Nanorods; Physics; Scanning electron microscopy; Sodium tungstate; Tungsten; Tungsten oxides; Tungsten trioxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.04.077

► Hydrothermal preparation of hexagonal WO 3 nanorods. ► Reversible electroactive hexagonal WO 3 nanorods. ► Structure-electroactivity relationship in hexagonal WO 3 nanorods. ► Hexagonal WO 3 nanorods as active support for Pt–Ru nanoparticles catalysis of ethanol electrooxidation. Tungsten trioxide, unhydrated with hexagonal structure (h-WO 3), has been prepared by hydrothermal method at a temperature of 180 °C in acidified sodium tungstate solution. Thus prepared h-WO 3 has been characterized by X-ray diffraction (XRD) method and using electrochemical techniques. The morphology has been examined by scanning and transmission electron microscopies (SEM and TEM) and it is consistent with existence of nanorods of 50–70 nm diameter and up to 5 μm length. Cyclic voltammetric characterization of thin films of h-WO 3 nanorods has revealed reversible redox behaviour with charge–discharge cycling corresponding to the reversible lithium intercalation/deintercalation into the crystal lattice of the h-WO 3 nanorods. In propylene carbonate containing LiClO 4, two successive redox processes of hexagonal WO 3 nanorods are observed at the scan rate of 50 mV/s. Such behaviour shall be attributed to the presence of at least two W atoms of different surroundings in the lattice structure of h-WO 3 nanorods. On the other hand, in aqueous LiClO 4 solution, only one redox process is observed at the scan rate of 10 mV/s. The above observations can be explained in terms of differences in the diffusion of ions inside two types of channel cavities existing in the structure of the h-WO 3 nanorods. Moreover, the material can be applied as active support for the catalytic bi-metallic Pt–Ru nanoparticles during electrooxidation of ethanol in acid medium (0.5 mol dm −3 H 2SO 4).