Effective electrode design and the reaction mechanism for electrochemical promotion of ammonia synthesis using Fe-based electrode catalysts

Abstract

The electrochemical promotion of ammonia formation on Fe-based electrode catalysts is investigated using proton-conducting-electrolyte-supported cells of H2–Ar, Pt |BaCe0.9Y0.1O3 (BCY)| Fe-based catalysts, H2–N2 at temperatures between 550˚C and 600˚C, and...

Kinetic and deuterium isotope analyses of ammonia electrochemical synthesis

“…The results are summarized as follows: (1) the ammonia formation rate has a positive correlation with H 2 partial pressure in the cathode, which agrees with the previous study. 38 (2) α and β do not change after applying different voltages, which indicates that the reaction mechanism is probably the same as that at the rest potential (surface reaction). (3) The contribution of surface reaction with EPOC to ammonia formation rate is larger than that of charge-transfer reaction with porous pure Fe, and the ammonia formation rate promoted by EPOC can be improved by increasing H 2 partial pressure in the cathode.…”

“…In our recent study, 38 we reported the following results: (1) a cathode structure with short triple phase boundary (TPB) length (i.e., porous pure Fe cathode) had better performance of ammonia formation rate than that with long TPB length (i.e., Fe-BCY cermet cathode), (2) the ammonia formation rate had a strong correlation with the H 2 partial pressure in the cathode. The ammonia formation rate increased from 2.2 Â 10 À9 mol cm À2 s À1 (71 mg mg À1 h À1 ) in 10% H 2 -90% N 2 to 1.4 Â 10 À8 mol cm À2 s À1 (450 mg mg À1 h À1 ) in 50% H 2 -50% N 2 using porous pure Fe cathode at 550 C and À1.2 V, which is equivalent to that in the Haber-Bosch process (250-976 mg mg À1 h À1 at 7-10 MPa and 400 C).…”

“…The results reveal an alternative route, i.e., surface reaction with EPOC, for electrochemical ammonia formation. Based on our previous study, 38 we believe that the effect of the EPOC is probably induced by the formation of an effective double layer via the spillover of proton originating from charge carriers in the electrolyte to promote the reaction of ammonia formation. Our ndings will aid in the design of new catalyst structures for the electrochemical synthesis of ammonia.…”

“…In our recent study, 38 we reported the following results: (1) a cathode structure with short triple phase boundary (TPB) length ( i.e. , porous pure Fe cathode) had better performance of ammonia formation rate than that with long TPB length ( i.e.…”

Favorable Role of the Metal–Support Perimeter Region in Electrochemical NH3 Synthesis: A Density Functional Theory Study on Ru/BaCeO3

“… 17 Recently, we proposed the formation of an effective double layer during NH 3 electrosynthesis with Fe/BaCeO 3 , which can be considered as an extension of the TPB active site model. 18 Several researchers have investigated the metal–support interaction in the electrochemical reaction and noted some similarities between this interaction and the electrochemical promotion effect. 19 An understanding of the complex relationship between these two factors is important for enhancing the electrochemical catalysis process.…”