cicCartuja Centro de Investigaciones Científicas de la cartuja

Artículo del mes 2018

A direct in situ observation of water-enhanced proton conductivity of Eu-doped ZrO2: Effect on WGS reaction

ICMS

Nuria García-Moncada, Luis F. Bobadilla, Rosalía Poyato, Carlos López-Cartes, Francisca Romero-Sarria, Miguel Ángel Centeno, José Antonio Odriozola Applied Catalysis B: Environmental 2018, Vol. 231, 343-356

Eu-doped ZrO2 solid solutions have been synthesized in order to prepare proton conductors as water-enhancer additives for the WGS reaction. Elemental characterization has been carried out revealing homogeneous dopant distribution resulting in fluorite-type solid solutions for Eu2O3 contents up to ∼9 mol.%. Representative samples of the Eu-doped ZrO2series have been analysed by Impedance Spectroscopy (IS) in inert, oxygen and wet conditions. The solid solution with 5 mol.% of Eu2O3 has presented the highest conductivity values for all tested conditions indicating an optimal amount of dopant. Moreover, the presence of vapour pressure results in an increment of the conductivity at temperatures lower than 300 °C, meanwhile at higher temperatures the conductivity is the same than that in inert conditions. To elucidate these results, in situ DRIFTS studies were carried out. These experiments evidenced the existence of water dissociation at oxygen vacancies (band at 3724 cm−1) as well as the presence of physisorbed water at temperatures up to ∼300 °C where the band at 5248 cm−1 characteristic of these species disappeared. These results points to a layer model where the physisorbed water interacts with surface hydroxyls generated by dissociated water that improves the proton conductivity through Grotthuss’ mechanism in the RT-300 °C temperature range. These samples were successfully tested in WGS reaction as additive to a typical Pt-based catalyst. The presence of the mixed oxide reveals an increase of the catalyst’ activity assisted by the proton conductor, since improves the water activation step.

Requisitos

  • Pertenecer a uno de los Institutos del cicCartuja
  • Ser menor de 31 años en el momento de presentar su solicitud
  • Ser el primer firmante del artículo
  • Haberse publicado en los últimos 6 meses
  • El trabajo debe haberse realizado, al menos en parte, en el cicCartuja

Los artículos seleccionados serán destacados como 'Artículos del mes' y participarán en el Premio de Investigación cicCartuja-Ebro Foods. Se concederá un Premio de 10.000 euros al ganador y dos Accésits de 5.000 euros cada uno al segundo y tercer clasificados.

 

Ver bases del Premio