Abstract:

Ni–Nb mixed oxides were prepared by two methods, conventional evaporation method and combustion synthesis. With the latter technique, the mixed oxide can be quickly prepared from an aqueous solution of metal precursors (oxidizers) and sucrose (fuel). The solids with a 0.15/0.85 Nb/Ni atomic ratio were characterized by different techniques including X-ray diffraction, scanning electron microscopy, XPS and Raman spectroscopy, and N2 adsorption–desorption measurements. Ni–Nb mixed oxides were tested in the oxidative dehydrogenation (ODH) of ethane to ethylene. The catalyst prepared by combustion synthesis (a technique that is simpler than evaporation method) showed a good performance in terms of activity and stability levels when compared to the catalyst synthesized by the evaporation method, even for long-term runs. Regarding the effect of the metal precursor, nickel nitrate and ammonium niobate oxalate generated the better catalyst in both synthesis routes. Surface activity for ethane consumption and ethylene formation was higher than that observed for the sample prepared by the evaporation method with the same metal precursors. Both prepared catalysts presented almost constant ethylene yields for 120 h in stream at 400 C and W/ F = 0.06 g s/cm3 (8% and 15% for combustion and evaporation synthesis, respectively) with a slight decrease over time on stream (13% and 11%).

Author affiliation: Santander, José Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina

Author affiliation: Lopez, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina

Author affiliation: Diez, Alejandra Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Author affiliation: Dennehy, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Author affiliation: Pedernera, Marisa Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina

Author affiliation: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina