Synthesis of ammonia directly from wet air using new perovskite oxide La0.8Cs0.2Fe0.8Ni0.2O3-δ as catalyst

Single phase perovskite oxide La0.8Cs0.2Fe0.8Ni0.2O3-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) Å3. Composite made of Ce0.8Gd0.2O2-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.