Synthesis of ammonia directly from wet air using new perovskite oxide La_0.8Cs_0.2Fe_0.8Ni_0.2O _3-δ as catalyst

Single phase perovskite oxide La_0.8Cs_0.2Fe _0.8Ni_0.2O_3-δ was synthesised to be used as electrocatalyst for electrochemical synthesis of ammonia directly from wet air. It exhibits an orthorhombic structure with space group Pnma(62); a = 5.5493(5) Å, b = 7.8352(10) Å, c = 5. 5295(5) Å, V = 240.42(4) ų. Composite made of Ce_0.8Gd_0.2O _2-δ (CGO) and (Li,Na,K)₂CO₃ was used as electrolyte. An ammonia formation rate of 9.21 × 10^-7 mol s^-1 m^-2 was obtained at 400 C when applied a voltage of 1.4 V, while wet air (3 mol% H₂O) was introduced to the single chamber reactor. This is just slightly lower than the value of 1.23 × 10^-6 mol s^-1 m^-2 when wet N₂ (3 mol% H₂O) was fed under the same experimental conditions. These values are more than two orders of magnitude higher than the reported ammonia formation rates when synthesised from N₂ and H₂O at ∼ 600°C. The perovskite catalyst is also low cost compared to the Ru/MgO and Pt/C catalysts in previous reports. This experiment indicates that ammonia can be directly synthesised from wet air using low-cost catalysts. This is a very promising simple technology for sustainable synthesis of ammonia in the future.