Electrochemical synthesis of ammonia from N2 and H2O based on (Li,Na,K)2CO3-Ce0.8Gd 0.18Ca0.02O2-δ composite electrolyte and CoFe2O4 cathode

摘要

Electrochemical synthesis of ammonia from water vapour and nitrogen was investigated using an electrolytic cell based on CoFe2O 4-Ce0.8Gd0.18Ca0.02O 2-δ (CFO-CGDC), CGDC-ternary carbonate composite and Sm 0.5Sr0.5CoO3-δ-Ce0.8Gd 0.18Ca0.02O2-δ (SSCo-CGDC) as cathode, electrolyte and anode respectively. CoFe2O4, CGDC and SCCo were prepared via a combined EDTA-citrate complexing sol-gel and characterised by X-ray diffraction (XRD). The AC ionic conductivities of the CGDC-carbonate composite were investigated under three different atmospheres (air, dry O 2 and wet 5% H2-Ar). A tri-layer electrolytic cell was fabricated by a cost-effective one-step dry-pressing and co-firing process. Ammonia was successfully synthesised from water vapour and nitrogen under atmospheric pressure and the maximum rate of ammonia production was found to be 6.5 × 10-11 mol s-1 cm-2 at 400 C and 1.6 V which is two orders of magnitude higher than that of previous report when ammonia was synthesised from N2 and H2O at 650 C.