ORALS

SESSION: PhysicalThuAM-R10	Vayenas International Symposium on Physical Chemistry and its applications for sustainable development
Thu Oct, 24 2019 / Room: Aphrodite B (100/Gr. F)
Session Chairs: Antonio de Lucas Consuegra; Dimitrios Niakolas; Session Monitor: TBA

12:10: [PhysicalThuAM03] Keynote
Electrochemical Promotion of Catalysis in Hydrogen Production Reactions
José Luis Valverde¹ ; Fernando Dorado² ; Estela Ruiz Lopez³ ; Antonio De Lucas Consuegra³ ; ¹University of Castilla la Mancha, 13071, Spain; ²University of Castilla La Mancha, 13071, Spain; ³University of Castilla La Mancha, Ciudad Real, Spain;
Paper Id: 55 [Abstract]

Hydrogen is a very important feedstock in the industry and a promising energy carrier with a main application in internal combustion engines and in fuel cell technology, as a clean and efficient alternative to the massive consumption of fossil fuels. Among the different methods for hydrogen production, catalytic routes are the most interesting ones, for instance via reforming and partial oxidation of hydrocarbons and biomass. In this sense, the addition of electronic promoters chemically (chemical promotion) or electrochemically (electrochemical promotion or EPOC) induces very significant and similar effects on catalytic hydrogen production reactions [1]. Both kinds of promotional phenomena follow the same general mechanism but the usefulness of the latter is highlighted. Hence the EPOC effect is based on the modification of the chemisorption properties of a metal catalyst by the electrochemical migration of promoter ions from a solid electrolyte support (via application of an electric current or potential) [2-3]. Hence, while in chemical promotion, a specific amount of a promoter is added during the preparation step of the catalyst. In the case of the electrochemical promotion, promoter ions are electrochemically pumped between the metal catalyst and the solid electrolyte in a controlled and reversible way during the reaction step [3]. Then, the electrochemical promotion presents several additional advantages, such as the possibility of optimizing the promoter coverage on the catalyst surface at different reaction conditions and the in-situ enhancement of the catalytic activity and selectivity. In this communication, the most important and recent contributions of our group in the electrochemical promotion of different hydrogen production reactions are reviewed. The functional similarities and operational differences between both promotion ways are pointed out, and their impact on the hydrogen production technology is discussed. By this method, the EPOC effects have shown a great interest in H₂ production technology by improving catalytic activity and selectivity under working reaction conditions. In addition, the in-situ catalyst regeneration from carbon deposition, and the possibility of applying the EPOC in the field of H₂ storage, among other novel contributions, lead EPOC to new opportunities in the H₂ technology. For these purposes, novel catalyst films were developed by means of different preparation techniques and also by means of operando surface analysis techniques such as in-situ near-ambient pressure photoemission (NAPP) spectroscopy have been used in order to investigate the origin and mechanism of this phenomenon.

References:
[1] J. Gonzalez-Cobos, J.L. Valverde , A. de Lucas-Consuegra, International Journal of Hydrogen Energy 42 (2017) 13712-13723
[2] P. Vernoux, L. Lizarraga, M. N. Tsampas, F. Sapountzi, A. De Lucas-Consuegra, J.L. Valverde JL, et al. Ionically conducting ceramics as active catalyst supports. Chem Rev. 113 (2013) 8192-260
[3] C.G. Vayenas, S. Bebelis, C. Pliangos, S. Brosda, Tsiplakides D. Electrochemical Activation of Catalysis: Promotion, Electrochemical Promotion and Metal-Support Interactions. New York: Kluwer Academic Publishers/Plenum Press; 2001.