| [Electrochemistry] High Temperature Proton and Co-Ionic Electrochemical Membrane Reactors a) Co2/H2o Co-Electrolysis and b) Nh3 Synthesis High Temperature Proton and Co-Ionic Electrochemical Membrane Reactors a) Co2/H2o Co-Electrolysis and b) Nh3 Synthesis Ioannis Garagounis1; Vasileios Kyriakou2; Anastasios Vourros1; Demetrios Stoukides1; Michael Stoukides1; 1ARISTOTLE UNIVERSITY, Thessaloniki, Greece; 2DUTCH INSTITUTE FOR FUNDAMENTAL ENERGY RESEARCH (DIFFER), Eindhoven, Netherlands; PAPER: 46/Physical/Keynote (Oral) SCHEDULED: 15:55/Thu. 24 Oct. 2019/Aphrodite B (100/Gr. F) ABSTRACT: Solid state proton conductors can operate at high temperatures (> 500 <sup>o</sup>C) and have been applied in the construction of sensors, fuel cells and hydrogen separators. In the past two decades, they have also been used in the construction of electrochemical membrane reactors. The advantage of high temperature conductors, versus those operating at low temperatures, is that they operate in the temperature range within which a large number of industrially important catalytic hydro-reactions and dehydrogenation reactions take place. In most of the earlier applications of electrochemical membrane reactors in catalytic research, the reaction of interest took place on the working electrode while the counter electrode served for the formation of protons from a hydrogen containing compound. These electrochemical reactors, however, would become more competitive if useful chemicals were produced on both, working and counter electrodes [1, 2]. Results on two reaction systems in which both, cathode and anode were properly utilized are presented here. The first is the production of methanol and oxygen from CO<sub>2</sub> and H<sub>2</sub>O. Steam and CO<sub>2</sub> are introduced at the anode and cathode side, respectively, of a co-ionic (H<sup>+</sup> and O<sup>2-</sup>) conductor. Steam is electrolyzed to form O<sub>2</sub> and protons (H<sup>+</sup>). The latter are transferred to the cathode and react with CO<sub>2</sub> to form CH<sub>3</sub>OH. The second system is an electrochemical Haber-Bosch (H-B) Process [3]. A mixture of steam and methane is fed to the anode chamber. Nitrogen is fed over the cathodic electrode. Hydrogen produced at the anode is "pumped" electrochemically (in the form of protons) to the cathode, where it reacts with N<sub>2</sub> to produce NH<sub>3</sub>. A preliminary energy analysis indicates that, at faradaic efficiencies above 30% and at cell bias as low as 0.4 V, the electrochemical H-B becomes more efficient than the conventional H-B Process with respect to both, energy consumption and CO<sub>2</sub> emissions. References: [1] S.H. Morejudo, R. Zanon, S. Escolastico, I. Yuste, H. Malerød-Fjeld, P.K. Vestre, W.G. Coors, A. Martínez, T. Norby, J.M. Serra, C. Kjølseth, Science, 353 (2016) 563-566. [2] A.Vourros, V. Kyriakou, I. Garagounis, E. Vasileiou, M. Stoukides, Solid State Ionics, 306 (2017) 76-81. [3] V. Kyriakou, I. Garagounis, E. Vasileiou, A. Vourros, M. Stoukides, Catalysis Today, 286 (2017) pp. 2-13. |
