Maria Escudero Escribano, who was recently named winner of the Princess of Girona Foundation Scientific Research Award, will give a seminar on Wed 11th at 12:00 with the title “Tailored Electrochemical Interfaces for Sustainable Energy Conversion”. 

Maria Escudero completed her doctroal thesis in our institute under the supervison of Angel Cuesta. After several years in Denmark and USA, she is now Assistant Professor at the University of Copenhagen.

ABSTRACT of her talk: One of the most important scientific and technological challenges facing humanity is the switch from fossil fuels to clean energy. Low-temperature fuel cells are expected to play a crucial role in a future society based on sustainable energy. However, the high platinum loadings required to compensate for the slow kinetics of the oxygen reduction reaction (ORR) impede the widespread uptake of these technologies. Platinum-based electrocatalysts can achieve high ORR activity and stability [1,2]. In order to improve the reaction kinetics and reduce the Pt loading, we need to develop more efficient electrocatalysts. In my talk, I will present two approaches aimed at tuning the electrode surface: atomic ensemble control [3] and electronic effects [1,2,4].

We studied atomic ensemble effects in electrocatalysis by using a self-ordered molecular pattern on Pt(111) single-crystals [3]. By selectively blocking the adsorption of spectator anions from the electrolyte while enabling the adsorption of reaction oxygen molecules, we could enhance the ORR activity [3].

The effect of subsurface alloying was studied on Cu/Pt(111) near-surface alloys [2,5]. The ORR activity as a function of the OH adsorption follows a Sabatier volcano relation both in acidic and alkaline media, suggesting that the ORR shares the same reaction intermediates in both electrolytes [2]. On the other hand, we studied the ORR activity and stability trends by controlling strain effects on Pt-lanthanide alloys [1]. The active phase consists of a Pt overlayer formed by acid leaching [6]. The activity versus the bulk Pt-Pt distance follows a volcano relation, the maximum activity corresponding to the optimum level of strain [1].

References

[1] M. Escudero-Escribano et al. Science 2016, 352, 73.

[2] K.D. Jensen, …, M. Escudero-Escribano, I.E.L. Stephens, Angew. Chem. Int. Ed. 2018, 57, 2800.

[3] D. Strmcnik, M. Escudero-Escribano et al. Nature Chem. 2010, 2, 880.

[4] M. Escudero-Escribano et al. J. Am. Chem. Soc. 2012, 134, 16476.

[5] I.E.L. Stephens et al. J. Am. Chem. Soc. 2011, 133, 5485.

[6] M. Escudero-Escribano et al., under review, 2018.