Nanoparticulated WO₃/NiWO₄ Using Cellulose as a Template and Its Application as an Auxiliary Co-Catalyst to Pt for...

This work reports the use of cellulose as a template to prepare nanosized WO₃ or NiWO₄ and its application as a co-catalyst in the electro-oxidation of ethanol and glycerol. Microcrystalline cellulose was hydrolyzed with phosphotungstic acid (H₃PW₁₂O₄₀) to prepare the nanocrystalline cellulose template. The latter was air-calcinated to remove the template and obtain nanometric WO₃. Tungsten oxide was impregnated with Ni(NO₃)₂, which was subsequently air-calcinated to obtain the nanometric NiWO₄. Elemental analysis confirmed the coexistence of nickel and tungsten, whereas thermal analysis evidenced a high thermal stability for these materials. The X-ray diffractograms displayed crystal facets of WO₃ and, when Ni(II) was added, NiWO₄. The transmission electron micrographs corroborated the formation of nanosized particles with average particle sizes in the range of 30 to 50 nm. Finally, to apply this material, Pt/WO₃-C and Pt/WO₃-NiWO₄-C were prepared and used in ethanol and glycerol electro-oxidation in an alkaline medium, observing a promotional effect of the oxide and tungstate by reducing the onset potential and increasing the current density. These materials show great potential to produce clean electricity or green hydrogen, contributing to energetic transition.